Nutrition 2.0: personalized approach

Hello everyone and Merry Christmas! Hope you all had a great time celebrating with your families and friends.

A few weeks ago the Internet exploded with articles referring to a revolutionary new study in the field of nutritional science. I am referring to the study from the Weizmann Institute of Science in Israel, published in a highly influential scientific journal Cell on Nov 19^th[1], which has conclusively proven the need for personalized approach to nutrition. The same research group was responsible for another mind-blowing article on how artificial sweeteners change the gut microbiome just a year ago in Nature [2]. Interestingly enough, the “personalized nutrition” idea turned out to be strong enough to take our minds off bacon for a while (bacon has been pronounced a Group 1 carcinogen, in case you have missed it.)

So what’s all the fuss about?

Our responses to certain foods are shaped by two factors, incredibly important to our overall wellbeing: hormones and gut microbiota. For instance, an excellent paper from 2 years ago linked higher cardiovascular disease (CVD) risk in red meat consumers with their gut microbiome composition [3]. Red meat lovers have different gut microbiomes than vegetarians, which makes sense if you consider another recent article that has demonstrated that even transient changes to our diet can significantly alter the gut microbiome [4], depending on which types of foods we preferentially consume (animal products or vegetables). The culprit in the case of CVD induction turned out to be not just red meat, but its component L-carnitine, which is also a prominent component of many supplements marketed to fitness freaks based on its proclaimed “fat-burning” properties.

Anyhow, our hormonal responses to food (particularly, insulin secretion), as well as composition and diversity of our gut microbiota [5] both largely affect how we process certain foods and whether or not we gain weight while exposed to a certain food environment. What Israelian scientists have now comprehensively demonstrated, is that blood glucose response (which essentially depends on insulin production) can be very different in different individuals who have eaten precisely the same foods. Seems obvious, right? However, up until now we have been largely taught that certain foods are “bad” for us and promote obesity, while others are “good” and beneficial for weight loss. Turns out, not really. Some people can consume sugar-laden baked goods without as much as an extreme blood sugar rise, while others will develop a strong reaction to plain bread. And it’s not necessarily the evil processed foods that are to blame. One example presented in the article was the response of two study participants to bananas and cookies: while eating a banana had almost no effect on blood sugar in one participant, his/her blood sugar spiked after eating cookies. Kind of what is expected, right? Bananas are naturally sweet, but not as bad as cookies, aren’t they? Well, for another participant they were: while eating cookies did nothing for his/her blood sugar levels, a nutrient-rich banana caused a profound spike of blood sugar levels. Moreover, it seems that having prevalence of certain microbial species in your gut microbiome is positively correlated with blood glucose level control. Not surprisingly, so are certain markers of metabolic syndrome (HbA1c%, for instance). Interestingly, adding more fat to the diet may or may not improve glucose response in some people, so the reaction to fat consumption is also very much individual. The amount of dietary fiber consumed was positively correlated with adequate blood sugar control in the long-term, even though it was, surprisingly, associated with increased glucose response immediately following the meal. The scientists also used a computational approach to design individual “good” and “bad diets” for study participants and monitored their blood sugar levels for a week. Not surprisingly, the “good diet” weeks were characterized by relatively stable blood sugar levels, while “bad diet” weeks featured huge spikes in blood sugar. It was, however, quite striking, how different those “good” and “bad diet” weeks were for individual study participants. Foods classified as “good” for some people were added to the list of “bad foods” of other people and vice versa, including both high-carbohydrate and high-fat foods.

The take home message of this study is relatively straightforward: there can be no universal nutritional recommendations (at least in terms of their effects on blood sugar). One size does not fit all, not only because some people naturally prefer meat to oranges or cookies to bananas. So maybe next time you try to jump on the latest trend bandwagon, don’t be surprised that it doesn’t work as good for you as you have anticipated. While some might thrive on a low-carb diet, others really need their carbs to function. And that’s totally normal, since if your blood glucose level control is in check and your microbiome is great at metabolizing carbs and sugar, it’s much less harmful for you to indulge in Christmas cookies that it is for some other people. Generally, if you know your body well and follow an intuitive eating approach, which is becoming increasingly popular these days (at least in part due to the increasing confusion in the diet camp and the guidelines on that to eat or not to eat rapidly changing), you might have already noticed how you feel in response to certain foods both short-term (if they make you tired or more energized) or long-term (if increased consumption of certain foods causes weight gain or chronic fatigue). Does it mean we should all trust our guts? Not necessarily. Ideally, as this study has taught us, the best way to determine your response to any kind of food is to monitor your blood sugar levels. Even though such tests are minimally invasive, I do not think that they are the best option for most people and are certainly not necessary (unless you are extremely curious and prone to n=1 experiments with your body – to those I say, go for it). Constant blood sugar level monitoring is, however, crucial for those who suffer from diabetes, since the standard diet recommendations might not fit your body’s needs. I guess such tests could also benefit those who already show insulin resistance and are at risk for developing diabetes.

Now, while it is clear that we are not all the same in terms of metabolism and blood glucose responses, the thing with gut microbiome and obesity (or other conditions), in my opinion, is sort of a “the chicken or the egg” story. While there are clear correlations between prevalence of certain gut microbes, as well as general microbiome diversity and obesity (or, as in this case, glucose responses), it is not quite clear what comes first: changes in diet that lead to changes in the gut microbiome and then to obesity (or they both go hand in hand) or do the changes in gut microbiota provoke obesity. This question, I think, does not yet have a clear-cut answer. While antibiotics have been linked to obesity in some studies, other studies have shown beneficial changes following antibiotic treatment since they may also eradicate the “bad bacteria” that contribute to disease. Also, I do believe that long-term dietary habits have a bigger role in shaping the gut microbiome than a single course of antibiotics. Other factors, such as bad dietary habits (lack of fiber, high sugar intake), definitely have a huge impact on the microbiome, however, those effects can be reversed once the diet is changed accordingly. Therefore, I do think that it is our diet that primarily influences the gut microbiota and diet-induced changes can then predispose us to certain conditions. Now, what kind of diet is good for each of us – that seems to be less clear than it used to be. The only advice that seems appropriate is that anyone who is interested in maintaining good health should not necessarily trust the latest dietary recommendations. But do throw in an occasional blood panel for good measure! I mean, preventing disease is always better than treating an already existing condition, and tests are not only for those folks who do not feel well. Our bodies are extremely robust and will tolerate our miserable lifestyles for years but at some point you really should start taking care of yourself.

With that I wish you a very happy, healthy 2016!

References:

1. Zeevi et al. Personalized nutrition by prediction of glycemic responses. In: Cell, 2015
2. Suez et al. Artificial sweeteners induce glucose intolerance by altering the gut microbiota. In: Nature, 2014
3. Koeth et al. Intestinal microbiota metabolism of L-carnitine, a nutrient in red meat, promotes atherosclerosis. In: Nature, 2013
4. David et al. Diet rapidly and reproducibly alters the human gut microbiome. In: Nature, 2014
5. Le Chatelier et al. Richness of human gut microbiome correlates with metabolic markers. In: Nature, 2013

How metabolic rate affects our lifespan and development

It’s been a while since I last posted on this blog. Today, my post is going to be dedicated to a rather broad scientific topic rather than addressing nutritional or fitness issues, even though it is often mentioned in popular literature on those topics. I am talking about metabolism.

Over the years, “metabolism” has become somewhat of a curse word in fitness circles. We loathe our slow metabolic rates and are constantly looking for a way to rev them up using exercise, diet or supplements. Somehow having a fast metabolism has become somewhat synonymous to being healthy and fit. In reality, we could not be more wrong. It is our slow metabolism that we have to thank for being one of the most long-lived species on Earth.

Metabolism is a combination of anabolic (synthetic) and catabolic (degradation) processes in the body. However, when we talk about metabolism in layman terms, we usually mean energy expenditure, our ability to burn calories to get energy. If an individual is able to burn a lot of calories without storing them as fat, this phenomenon is often referred to as “good/fast metabolism” and vice versa. What is quite curious, in fact, is that we, humans are supposed to burn about twice as many calories per day based on our body size. This is not specific to us humans – in fact, all primates are expected to burn more calories if compared to other mammals of similar body size, but they don’t. And that’s a good thing! It is our slow metabolic rate that leads to similarly slow processes of development, growth and reproduction cycles and, ultimately, to longer lifespans.

In a recent study [1], scientists compared total energy expenditures (TEE) in various primate species, including humans, with other placental mammals. Surprisingly, TEE of most primates was about half of what was expected of animals of their body mass. Such low TEEs apparently had nothing to do with physical activity (wild and captive primates appeared to have the same levels of energy expenditure) and rather seemed to result from a metabolic adaptation throughout history. That would at least partially explain why even vigorous exercise is not sufficient to drastically change our metabolic rates. Now, why do we have such low metabolic rates and how is this beneficial for us? While one of the theories suggests that low TEEs evolved as a protective strategy against starvation, there is no clear answer to this question. However, it is quite clear that increasing TEE and BMR (basal metabolic rate) can have rather devastating consequences, since their levels appear to be very tightly controlled. TEE is, of course, different from BMR: BMR represents the amount of energy required to fulfill basic requirements of the body to keep us alive. Interestingly, in the above mentioned study [1] they showed that primates’ BMR appeared to be higher, relative to TEE, than in other placental mammals, which was explained to reflect the metabolic cost of primates’ large brains. BMR depends on our age, sex and weight and is not easy to manipulate through various interventions, which is probably a good thing. Increasing BMR more than 2-fold of normal level seems to have devastating consequences on the organismal well-being. One condition known to drastically increase BMR is pregnancy, and it is the increase in BMR that we apparently have to thank for it lasting just 9 months and not longer.

It is a widely known fact that we, humans, are born pretty helpless and remain as such throughout the first months after birth. One of the reasons for such altriciality is the fact that we are born with a brain approximately 3 times smaller than we need for normal functioning (30% of adult brain size). This fact has intrigued scientists for years, and one of the common explanations for small at birth brains in anthropology used to be the so called “obstetrical dilemma”. According to it, we are born with such small brains simply because otherwise we won’t be able to pass through the birth canal, and a larger birth canal seems to be incompatible with bi-pedal locomotion. A recent study [2] substantially challenged this view. Based on their calculations, a wider birth canal is very well compatible with locomotion; therefore, it cannot be the limiting factor to the duration of pregnancy. The authors propose an alternative hypothesis: we are born rather early because our mothers’ BMRs reach values close to maximum sustainable metabolic rate (BMR x 2.1). If the intrauterine development periods were longer, this limit would have been quickly exceeded. Therefore, our metabolism simply cannot be driven into overdrive.

Now, what can we learn from this? We are, in fact, rather helpless when it comes to altering our metabolic rate and for good reasons. Having a fast metabolism is not necessarily a good thing. Hormonal disruptions, such as hypothoroidism, also affect metabolic rate and can lead to what is described as “sluggish metabolism”, but otherwise our metabolic rate seems to be predetermined. Lowering rather than increasing metabolic rate seems to be a promising strategy to achieve maximum longevity.

So what do you say, should we stop chewing on chili peppers and embrace our slow metabolism?

1. Pontzer er al. Primal energy expenditure and life history. PNAS, 2013
2. Dunsworth et al. Metabolic hypothesis for human altriciality. PNAS, 2012

Prevent cancer by changing your lifestyle

pic source: blog.aicr.org (American Institute for Cancer Research)

There is definitely more to gaining excess body fat than just not being able to fit into your favorite jeans – being obese can also increase your cancer risk. While there are people who have been technically overweight their entire life and are perfectly healthy, becoming obese (BMI>30), especially if that body fat is mostly centered around your abdomen, is a medically defined risk factor for getting certain cancers, among those cancers of the digestive system (oesophagus, colorectum, gall bladder, pancreas), as well as breast cancer (in postmenopausal women), ovarian and kidney cancer. According to the “European Code against Cancer, 4^th edition” [1], about 4-38% of these cancer types can be attributed to obesity. Though these figures might sound grave, there is also good news: losing weight dramatically diminishes cancer risk! However, even if you are at normal weight, healthy diet, active lifestyle and moderate-to-low alcohol consumption are highly advisable as means of cancer prevention. That means, it is totally up to you to decrease your cancer risk.

So what is it about excessive body fat that makes it so dangerous? After all, isn’t it just our energy stores? Not exactly. It has been widely recognized lately that body fat is a metabolically active tissue that produces hormones and cytokines (adipokines and pro-inflammatory cytokines). Increased body fat accumulation can also lead to hormonal imbalances, e.g. insulin resistance. Due to disruption in sex hormone production, obesity can also cause infertility in women (that can be cured by losing weight). Insulin and hyperinsulinaemia can also stimulate cancer cell proliferation and tumor growth. Hyperinsulinaemia can indirectly promote cancer by increasing the circulating levels of insulin-like growth factor 1 (IGF-1), which has been linked to cell proliferation, as well as aging. Leptin, produced by the fat tissue, can also be pro-inflammatory and favor cancer-friendly environment.

So what are the official recommendations of European Code against Cancer? As stated in a recent article (see [1]), they are pretty much common knowledge: don’t smoke, limit your alcohol intake, avoid too much sun exposure, eat a healthy diet, be physically active, try to achieve normal body weight. Last but not least: don’t forget to undergo regular check-ups. Even if you are doing your best to live a healthy life, it does not hurt to pay a visit to the doctor’s office once in a while!

(1) This post is based on the following article:

“European code against cancer 4^th edition: Obesity, body fatness and cancer” by Anderson AS et al in Cancer Epidemiology 2015.

If only you could turn back time… Can you?

Hello there, dear readers! Long time, no see… Today’s post is dedicated to the best reason to invest some energy into maintaining a healthy diet and activity regimen.

Overall, there are plenty of good reasons to exercise and eat healthy: weight loss/maintenance, radiant health, avoidance of typical “lifestyle diseases”, such as obesity and type II diabetes, and, of course, feeling great. But what if eating healthy and maintaining an active lifestyle could do more than that? What if they could fight back aging?

Image source: leadershiptraq.com

Anti-aging treatments are all the rage now, but are any of them actually effective? Apart from concealing the appearance of some side effects of aging, such as graying hair or wrinkles (which are basically harmless), there is no treatment for aging, no “anti-aging pill”. And why should there be? Aging is not a disease. Getting old is as natural as going through puberty. There is also no reason you cannot enjoy life after you turn 60, 70 or 80. That is, of course, if you are healthy. Healthy aging does not necessarily come with memory loss, frailty or motor impairments, like some of us have come to believe. But the even more devastating consequence of aging is increased susceptibility to disease. This is partially due to the fact that immune system function decreases with age, but also due to accumulation of mutations and other changes, such as oxidative damage to molecules at the intracellular level. However, there is a way to maintain a healthy immune system with increasing age. Luckily, it is the same trick that may allow one to remain sharp and think clearly until 100 years of age and above – and, as you might have guessed, it’s again eating right and exercising. Apart from that, stress relief, healthy social interactions with peers and family, as well as moderate sun exposure and good sleep are also part of the equation. But what if all those interventions could not only help you fight the symptoms of aging, but reprogram your body so that it actually gets younger with increasing age? Well, seems like this scenario is not such an unlikely possibility.

The reason why appropriate nutrition and meal timing/frequency, as well as certain types of exercise can do your body a lot of good is because they have the capacity to actually alter your gene expression. But wait, our DNA does not change much throughout lifetime – it would not make a lot of sense, since the cell does everything to preserve the initial sequence. However, there is a way our cells can switch genes on and off again without doing any changes to the DNA sequence itself. It can do so by altering (in a reversible way) the proteins that participate in DNA folding and packaging in the nucleus – histones – by attaching certain molecular anchors to them. Such changes are referred to as epigenetic changes and they have huge potential to alter cell physiology for a short or long period of time. There is a bunch of epigenetic changes described so far, and not all of them involve histones. The common thing between them is that they act in a modulatory way and can respond to changes in the environment. But if you think that such changes cannot stick, think again: actually, it has been demonstrated that epigenetic changes can even be transmitted to the next generation! It means if you have accumulated beneficial (or not so beneficial) changes in your cells, they can be passed on to your offspring. Another great reason to keep your lifestyle in check!

There is substantial evidence that exercise and moderate caloric restriction can produce a lot of beneficial changes, but what about reversing or slowing down aging? Well, I have a reason to believe that lifestyle changes can produce such effects. There is a lot of so called (by scientists) anecdotal evidence from people who have converted to a healthier lifestyle that they feel and even look younger. Is it just a subjective perception? Not necessarily. A recent study from Duke University [1] has demonstrated the first attempt to quantify aging in young adults. [NB: The term “young adult” is this case does not refer to teens who love Twilight novels, but rather to people who are well into their 30s – all participants were around 38 y.o.] The results of the study are quite stunning, in my opinion: they have found that, even though all participants were roughly the same age, their actual, biological age followed a normal distribution, ranging from 28 y to 61 y. So it means that while some participants were actually still in their 20s, according to their body, others were almost twice as old as they were supposed to be! Some participants appeared to be getting younger, as the study progressed (the scientists have actually measured aging biomarkers at different time points leading up to the age of 38: at 26 y, 32 y and 38 y). The study does not report any differences in lifestyle among the participants – it was not the focus of the study, since the merely wanted to measure the range and the speed of biological aging (the Pace of Age, as they termed it). However, the biomarkers they used to determine biological age lead me to believe that lifestyle choices have much more to do with the speed of aging than genetics (in fact, so far genetics is thought to have a roughly 20-30% contribution to how we age). So, unless you have certain mutations that cause progeria (premature aging) or extremely lucky to carry one of the very few mutations that naturally predispose you to longevity (such as mutations of the FOXO3a gene), there are ways to alter the speed at which your body ages and may be even reverse or stall it. For instance, one of the participants of the above mentioned study seemed to be getting younger during the 12-year study process! Here are some of the 18 biomarkers they used in the study: HbA_1C (glycated hemoglobin, indicates plasma glucose levels over prolonged periods of time), cardiorespiratory fitness, waist-to-hip ratio, mean arterial pressure, BMI, lipoproteins, triglycerides, gum health, total cholesterol and HDL cholesterol. Looking over this list, I don’t see anything that is not manageable by healthy lifestyle choices. Glycated hemoglobin levels and blood lipid profile respond very well to a balanced diet including healthy fats and plenty of fiber and excluding sugar and excessive carbs. Healthy waist-to-hip ratio and BMI can both be maintained on a balanced diet (even though BMI is not the best marker of overall health); at the same time, it is also by far the best intervention to decrease blood pressure. Ditto for gum health – excessive sugar consumption is not only bad for your teeth, but also for your gums. As for the cardiorespiratory fitness – you’ve guessed it – moderate exercise and increasing overall physical activity are the best remedies. And exercise does not necessarily or only mean cardio, as the name would imply: a combination of resistance and cardio exercise is considered to be the gold standard for achieving an optimal state of physical fitness.

And if normalizing your biomarkers isn’t stimulating enough, consider this: study participants of a younger biological age were also perceived as younger-looking by an independent group of observers! So not only may healthy lifestyle pay off by making you, well, healthy, but you’ll save a great deal on those anti-wrinkle creams!

1. Belsky et al. Quantification of biological aging in young adults. Proceedings of National Academy of Sciences USA, 2015 (www.pnas.org/cgi/doi/10.1073/pnas.1506264112)

Intermittent fasting vs. caloric restriction, v1.0

Caloric restriction (CR) gets a bad rep because of all the crash diets associated with it. However, restricting your calories to 70% of what you would normally consume can boost your brainpower and even delay aging! (1) Another recent study in humans using a similar dietary regimen (30% reduction in calories) found that CR induced dramatic transcriptional changes in skeletal muscle, making the transcriptional profile of older humans more similar to the one of young people (2). CR has the potential to decrease inflammation, increase mitochondrial biogenesis and down-regulate the activity of IGF1/insulin receptor pathway – major aging regulator. Therefore, caloric restriction induces metabolic changes that lead to lifespan extension and improve insulin sensitivity (3).

If CR is, basically, the miracle anti-aging drug we’ve been looking for, why don’t we all just cut our calories? Well, if you’ve never been on a diet before, let me tell you – it’s not that fun. Consistently living on a caloric deficit can make you feel less energetic and cold, never mind the fact that you would actually have to keep track of the calories you consume.

Enter intermittent fasting.

Couple of years ago, fasting was a “no-no” in dieters’ circles. Everyone had heard by that time that fasting could slow down metabolism. Well, apart from the fact that our metabolism is not as much affected by our dietary manipulations as we’d sometimes like it to be (it is, though, I’m not saying it’s not), fasting every once in a while also has major benefits for our bodies. That is why different intermittent fasting regimens are all the rage right now.

Intermittent fasting (IF) is fasting interrupted by eating – or the other way round. In other words, as opposed to long-term fasting regimens, IF protocols can easily be integrated into a normal routine without feeling deprived. The best thing about intermittent fasting is that it can induce similar beneficial changes in your body as CR regimens without actually reducing the number of calories consumed. For instance, IF can reverse negative effects of metabolic syndrome and improve glucose metabolism. Fasting is also beneficial in human diseases with chronic inflammation involvement (such as rheumatoid arthritis, asthma). Fasting can reduce oxidative stress, increase neurotrophic signaling, improve cellular bioenergetics, promote synapse formation and neurogenesis (3). By activating autophagy (a “self-eating” intracellular mechanism which leads to destruction of damaged macromolecules and organelles), fasting shows positive effects in cancer prevention.

There are multiple IF protocols out there, and all of them can be quite effective (fasting 24h once or twice per week, skipping breakfast every day, fasting every other day, eating 1 meal per day and so on). My personal favorite is the Leangains protocol, which basically allows you to eat normally every day – you just have to maintain a 14 (for women) or 16 (men) hour window between your last and your first meal of the day. So you go through an overnight fast (a.k.a. sleep) and then go several additional hours without eating. Drinking black coffee, tea and, of course, water is allowed. If you prefer to have breakfast, you can skip dinner and fast until the next morning.

However, in some cases, fasting can be detrimental. For instanse, women have to enjoy intermittent fasting with a lot of caution or avoid it altogether, especially if they are trying or planning to get pregnant. A widely cited recent study in rats has shown that intermittent fasting can have negative effects on reproduction. While the results from animal studies have to be considered with caution, there is definitely something to think about. Anyway, the overall nutrient status of your diet seems to be much more important than total calories consumed with or without fasting (more on that later). I am not a medical doctor, so I cannot really offer recommendations here, but I would strongly suggest women to be very careful about fasting. I have tried it myself and have seen some benefits in the short-term, however, after a couple weeks of regular 16h fasts I started having troubles falling asleep. I have then read that sleeping problems can be an early sign of elevated cortisol levels, which happens quite often on fasting regimens. So, to sum it up, if you are healthy, not planning to get pregnant and want to try IF – go ahead! But pay very close attention to your body signals. If you notice some sleep problems or something else which seems weird, discontinue immediately!

Most important take-home message: Fasting has to be combined with a nutrient-rich diet, otherwise the benefits will probably not last! Same goes for caloric restriction. Nutrients before calories. Therefore, intermittent fasting can be a nice add-on to an overall healthy lifestyle, but fasting or restricting calories alone is not enough and can even be detrimental for some people. However, if you had to chose between the two regimens (IF vs. life-long caloric restriction), IF regimens are probably much easier to adhere to in the long-term perspective.

References:

1. Witte et al “Caloric restriction improves memory in elderly humans” PNAS 2009
2. Mercken et al „Calorie restriction in humans inhibits the PI3K/AKT pathway and induces a younger transcription profile“ Aging Cell 2013
3. Stranahan & Mattson 2012 „Recruiting adaptive cellular stress responses for successful brain ageing“ Nature Reviews Neuroscience 2012

On finally getting to know yourself

I was planning my next post to be on the benefits of intermittent fasting vs. caloric restriction, but, due to a bout of sudden inspiration I had at the gym, I’ve decided to write about something completely different today. And it is going to be very personal.

In one of my all time favourite comedies, Simon Pegg is faced with a harsh reality of publishing business: once you’re in, you’re only in the first room. You’d have to get to the seventh, if you want to be considered a success and achieve greatness. Well, that pretty much is true for whatever you do in life. However, the definition of greatness can vary. What is the Shagri-La of fitness? Who has been more successful in getting to it: a bodybuilder-slash-fitness maniac with a perfect-looking body, counting each calorie or maniacally hooked on Paleo or someone who is healthy, fit, though imperfect, but mentally stable, eating intuitively when needed and exercising mindfully? For a long time, I thought the first option was the only one worth striving for. Now, I’ve come to emrace the latter. How did it happen?

Well, I’ve come a long way to accept and love myself the way I am. I would actually say, I’m still on my way. I’ve been battling an anxiety disorder my whole life, and I’ve come to realize it just recently. My anxiety has shown its ugly head in multiple ways throughout my life, but its fitness-relevant manifestation started when I was 14 years old. It was then when I suddenly saw myself as fat and disgusting as opposed to  a happy and healthy teenager I actually was.

Me in Japan with my parents when I was 14 yrs old.

It was then when diets entered my life and they never quite left. You name any diet in the book – I’ve tried it. Of course, as you might have guessed, t the end of this journey I was left with bitter regret, health problems and several extra pounds that would not leave my body. Thankfully, this diet craze went into remission for a while when I had entered university at 17 and started to have other things to obsess about. Then, at 23 I moved to Germany, gained a couple extra pounds and, finally, at 26, it all started again. This next time around, however, I did come to realize something very important: I needed to change my lifestyle in a consistent way, if I didn’t want to repeat my mistakes from 10 years ago.

It was then when I started exercising consistently. Fitness entered my life in a completely new perspective, but my mind-set was still focused on the goal, not the process. I’ve started trying on lifestyles, not diets this time. I tried clean eating, I tried fasting, I tried vegetarianism, I tried Paleo. I went from eating pasta to low-carb, from swearing off meat to eating meat every day. Again, I got so caught up in dogmas and restrictions that I completely forgot to actually listen to my body. I gained, I lost – the all too familiar merry-go-round. I was still blaming myself for not sticking to meal plans, exercise plans, for eating too much sugar, for skipping the gym from time to time.

It finally stopped at some point, when I entered that glorious seventh room in my own head.

I have come to realize that I do not need any kind of plans to be healthy. I do not like plans – I enjoy being spontaneous. I cannot follow a plan and not become obsessive about it. I cannot follow a diet or count calories for the very same reason. I’ve read a lot on intuitive eating and it actually does appeal to me very much. However, yet again, I’m not going to adat any kind of eating style. I eat what I want, I exercise because I like it. I only do what makes me happy. If what makes me happy also makes me fit and healthy – hey, that’s just great! I don’t know if you would have come to realize this without going through all the diet madness I’ve been through. Maybe I should have realized it long time ago. It took me 15 years to finally be in peace with myself, and something tells me that this journey of finding peace is not quite over. But it is what it is – a journey. A process of finding oneself is the most glorious, exciting thing in life. Celebrate your own journey!

What does not kill you makes you stronger

Even poisons and toxins can sometimes be good for you, if consumed properly and in tiny amounts. No, I’m not talking about homeopathy. There are much more pleasant ways to ingest potentially dangerous substances, and most of us do it on a regular basis – fancy a glass of wine after a tough workday? Some studies have reported beneficial effects of light-to-moderate alcohol consumption, and alcohol consumption has also been associated with reduced sudden cardiac death risk (Albert CM, Circulation 1999; Chiuve SE, Heart Rhythm 2010; Bertoia ML, Am J Clin Nutr 2013), although this association is still quite debatable. But what is the reason behind this? When discussing health-related effects of alcohol, red wine usually comes to mind as a “healthy” alcohol source (remember the Mediterranean diet and “the French paradox”?). Interestingly, the above mentioned studies meant alcohol per se, any reasonable sourse of EtOH, not red wine only. What could be behind the seeming benefits of alcohol consumption?..

Another common “toxin” that we ingest on a daily basis is fructose. If it’s coming from natural sources, coupled with lots of fiber (read: fruit or berries), it’s actually not that bad for you, but the way it’s metabolized in the liver (which is very much similar to the way alcohol is metabolized), suggests it is regarded as a toxin by the body. Also, if you think about how bad it is for us when consumed in pure, isolated form (read: high-fructose corn syrup), it actually does make sense. So why is eating fruit commonly viewed as a vital part of an overall healthy diet?

Let me guess your answer: antioxidants.

Fruits and vegetables are healthy because they contain a lot of antioxidants.

What can I say to that? Yes, as a matter of fact, they do. But that’s not what makes them healthy.

First of all, antioxidants consumed from food or supplements are far less powerful than the ones produced by our own body when oxidative stress response mechanisms are activated. Also, certain levels of oxidants are not only healthy – they are crucial to certain functions on the intracellular level. Of course, when we talk about oxidative stress in a pathological condition (e.g., atherosclerosis), the levels of oxidants produced are far exceeding the beneficial levels. But I digress! So what is it in the fruit that makes it good for you? Hint: the underlying mechanism also contributes to the benefits of intermittent fasting, caloric restriction, exercise and intellectual challenges.

By now you might have guessed that I’m talking about some kind of “good stress” type of thing here. The “good stress” – “pre-conditioning”, if you will – I’m referring to is hormesis. “Hormesis is what makes fruit and vegetables healthy, not antioxidants”, to cite Mark Mattson (Mattson & Calabrese, New Scientist 2008). So what is hormesis? The term originally comes from the field of toxicology and refers to the ability of some drugs to induce a biphasic response by having a toxic effect at high doses but a beneficial one at low doses (see Fig.1). Alcohol, for example, is discussed as a potential inducer of hormesis, although it has never been proven. Many trace minerals in our diet work in a hormetic sort of way: for instance, selenium is absolutely essential to our well-being, albeit at very small doses; however, it can be very much toxic at moderate and high doses. The same is true for oxygen: we literally can’t breathe without it, but give us too much and it becomes toxic to us. Same thing happens when we eat fruits and vegetables, which contain certain phytochemicals that induce hormesis, such as: sulforaphane (broccoli), resveratrol (grape skins), curcumin (turmeric), caffeine (coffee), ECGC and other catechins (abundant in green tea, but also present in black tea). All these plant substances are potentially toxic for us, and yet they have proven to be quite beneficial when consumed at low doses. Moreover, the response they initiate in our cells is probably the main reason behind the health benefits of fruits and vegetables, not so much because they contain antioxidants.

Figure 1. Hormesis. Adapted from Gems & Partridge, Cell Metabolism 2008.

Hormetic response induced by fruits and vegetables is a result of an adaptation that has occurred at some point during the course of evolution: our organisms have evolved in a way that we can consume stuff containing potentially dangerous substances (like biopesticides) and get away with it! Why the heck did we start eating plants in the first place, anyway? Energy and nutrients, that’s why! (Also, plants cannot run away from us like animals – that’s why they counterevolved to produce all those dangerous things in the first place.) So to manage toxic chemicals those plants contain, we evolved to obtain certain detoxification mechanisms to metabolize and excrete these “poisons”, but also to use those substances to our advantage by activating certain pathways in the cells that are beneficial to us in the long run. Isn’t that grand? Smart little buddies, our cells.

Some phytochemicals (in particular, phenolic compounds) can directly act as antioxidants, but their concentration in the plants is so low, that we, humans, would have to eat enormous, unrealistic amounts of fruits and vegetables to reach an appropriate concentration of plant antioxidants on a cellular level. Instead, what happens is that phytochemicals – those potentially harmful at high doses biopesticides produced by plants – activate intrinsic antioxidative defense systems, like the Nrf2 pathway. Activation of stress-response pathways in the cell results in a protective effect that can counteract detrimental effects of aging or disease on the organism. So, basically, phytochemicals are slightly poisonous to the cells, making the cells more robust to more detrimental stressors. But if you overdo it with phytochemicals, it might result in cell death. What does not kill you makes you stronger, indeed. Fortunately, noxious effects mostly occur before a highly toxic and dangerous amount of phytochemicals is consumed.

Consumption of phytochemicals (through fruits and vegetables or via supplements) can increase resistance to many types of stressors on the molecular, but also on the organismal level. It can lead to stimulation of internal antioxidative activity, protect against harmful effects of inflammation, support energy metabolism and activate clearance of damaged macromolecules. All those protective effects are especially important to the aging population, since phytochemical-induced responses can potentially counteract age-related changes. Indeed, animal studies confirmed a positive effect of citrus fruit and berry extracts (which contain an active compound quercetin) on lifespan and demonstrated their various anti-aging properties. Curcumin, resveratrol and EGCG (the main active polyphenol in green tea) act on the insulin receptor pathway – a major intracellular pathway that regulates aging, growth and, of course, insulin sensitivity. Resveratrol and EGCG are also known to activate sirtuins, particularly SIRT1, that targets multiple proteins involved in numerous stress response pathways, activation or blocking of which can lead to decreased inflammation, Alzheimer’s disease (AD) and cancer risk. Not bad, huh? So why don’t we just treat AD patients with those fruits and veggies?

Unfortunately, when it comes to disease prevention and disease management, plant phytochemicals seem to be more useful for the prior. Once the disease is at an advanced stage, not much can be done. Small beneficial effects produced by the ingestion of plant phytochemicals might be of no use anymore when a person is already very sick, and more harsh interventions are needed. Nevertheless, some phytochemicals (e.g., cannabinoids) are being used in clinical studies and to manage certain conditions. Drugs based on natural phytochemicals are being developed and widely investigated. Word of advice, though: why wait for the drug, when you can treat yourself to/with fruits and veggies to promote health and enjoy their delicious taste? Pair them with a good cup of coffee – caffeine decreases depression risk – or green tea, and you are good to go!

For a more detailed overview of various phytochemicals that can induce hormesis and mechanisms of their action, I’m referring you to an excellent and very extensive review by Lee and Mattson in Pharmacological Reviews, June 2014, entitled “Adaptive Cellular Stress Pathways as Therapeutic Targets of Dietary Phytochemicals: Focus on the Nervous System”.

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Other hormesis-inducing agents that are crucial to health maintenance include intermittent challenges, such as high-intensity interval training or fasting for short periods of time. How does challenging yourself intermittently improve health and what are the benefits of intermittent fasting vs. simple caloric restriction? Stay tuned!

On defining fitness & practicing what you preach

As I’ve mentioned in the intro, this blog is dedicated to all topics around maintaning and/or gaining fitness. Before we start to explore possible ways of doing so, it is important to understand what fitness actually is. Most people usually think of fit, lean, athletic bodies of bodybuilders or sportsmen, when they hear the word „ fitness“. Yes, fitness is generally associated with the ability to perform certain physical activity. But it is so much more than that!

Fitness, as defined by Collins English Dictionary – Complete and Unabridged. (1991, 1994, 1998, 2000, 2003) is:

1. the state of being fit
2. biology: the degree of adaptation of an organism to its environment, determined by its genetic constitution; the ability of an organism to produce viable offspring capable of surviving to the next generation

Although the ability to adapt to the environment and produce offspring can fit into the first definition – being fit – these topics are beyond the scope of this blog und my general interests 😉 That leaves us with „the state of being fit“. The generalization of being fit means that it encompasses so many states at the same time. There is physical fitness, which is characterized by the ability to maintain a healthy, strong body. There is mental fitness – the ability to perform complex mental tasks well into advanced age. Train your body – train your mind. Actually, as you will discover, training your body also keeps your mind sharp! But more on that later…

Being fit in a sense equals to being happy and content. To lead a life of excellent fitness, there are certain rules you have to obey. Based on a heap of scientific (and not so) literature on health & fitness I’ve encountered so far, these are the general guidelines you should follow:

1. Keep your nutrition in check
2. Be physically active (basically, any kind of activity will do!)
3. Sleep well and avoid chronic stress
4. Have a satisfying social life
5. Keep your brain sharp (by learning new stuff)

However, the means you should use to achieve your health goals (e.g., eating better) are highly disputed. Should you count calories or carbs? Should you avoid carbs alltogether? What about cholesterol? (A lot of confusing and potentially contradictory data out there on that one!) To make an already bad situation even worse, a lot of nutrition and exercise myths are still circulating around, even in scientific literature. One thing that never seizes to amaze me is how ignorant people are towards the fact that certain „resistant“ food myths are not based on real science or have been disproved by it years ago. Even some of my fellow scientists (myself included!) do not always associate the facts they read about in scientific papers with certain habits they follow in their daily life. Once I had an interesting conversation with a colleague, in which I had to explain to her how our blood cholesterol levels do not have much to do with our dietary fat consumption. She seemed genuinely surprised by that, which I found kind of shocking. On the other had, isn’t that something I had (or hadn’t) thought of before? Wasn’t I the one who was buying low-fat milk for ages? Combining theory with everyday life is hard. I hope that my notes here are going to be helpful to someone out there struggling to get through all the confusing facts we are being constantly bormbarded with in terms of fitness. More importantly, I hope that in the process of making these notes, I’ll be able to take a good, hard look on my own habits and maybe change them for the better or find new opportunities to experiment.

Coming up next: what do intermittent fasting, eating a diet full of fruits and vegetables and exercise all have in common (besides making you fit & healthy)? Stay tuned!

(pic from memegenerator.net)

Hello there, fitness & health geeks!

This blog is dedicated to sharing my knowledge on fitness and health from a scientific point of view. My aim is to combine my knowledge as a scientist with some experience (a.k.a. self-experimentation) with different approaches to nutrition and training.

There is a lot of information on dietary recommendations and fitness out there. If you are really into this topic, you will also notice that it tends to be somewhat paradoxical and confusing. Therefore, one has to resort to science-based approaches (a.k.a. critical analysis of the literature) in order to separate the wheat from the chaff, so to speak (gluten-free craze, anyone?).

Finally, the real goal of this blog is not only to share the data with you geeks out there, interested in maintaining health, but to make them understandable to people who have no interest in spending hours and hours digging through the literature to know how to exercise and eat well.

So let´s buckle down and get to work!