Does Intermittent Fasting Increase Lifespan?

Some say feasting and fasting will keep you younger. (Photo by bowtoo)

I often hear or read that intermittent fasting has all of the same benefits of calorie restriction. The idea is that by not eating every now and then while keeping total calories the same you would enjoy the same health effects as you'd get from simply eating less. Including living longer.

This mantra is repeated even in scientific papers, but is it correct? It's certainly easy to see the appeal: since actual calorie restriction means you're counting every calorie and going hungry for most of the time, intermittent fasting seems like a fantastic choice. Besides, the concept does make sense on the surface. Deprive your body of energy for a while, let autophagy do its work, and live longer. It seems to work for fruit flies and worms, after all, so why not humans?

Because humans are more complex. While simple species like roundworms can be very useful for screening life extension therapies, they are no guarantee that the same therapies work in humans. There are a million ways to extend lifespan in roundworms and fruit flies, but much less in rodents, and even less in humans.

Unfortunately, it looks like intermittent fasting (IF) is one of these cases. For obvious reasons, we don't have lifespan studies on IF in humans, but what we do have is studies on rats and mice. And, despite what the popular belief is, the data is much less promising than one might hope. The rather disappointing conclusion of the studies seems to be that intermittent fasting without caloric restriction does not extend lifespan. When it is accompanied by caloric restriction (CR), it does extend lifespan – and it looks like the degree of life extension is highly dependent on the degree of CR.

The reason you see studies showing increased longevity from IF in the first place is because most rodents eat less when they fast every other day. While humans generally compensate for a fast by eating twice as much the next day, mice and rats generally don't. They do eat more, but not twice as much – which means they are calorie restricted.

Don't believe me? Let's take a look at all the studies on intermittent fasting and longevity in mammals. Note that I've skipped all the alternate-day feeding studies that have not looked at lifespans. There are a lot of papers showing other kinds of health benefits from fasting (some of which are also a result of CR!) , and I'm not saying fasting is not healthy in general, just that it does not seem to extend life.

A critical look at the studies

The first paper I could find on the subject is from 1945 (link), not too long after the positive effect of calorie restriction on lifespan was discovered. This paper briefly mentions an even earlier study from 1934, in which mice fasted for two days in a row each week. The average lifespan of the fasted mice was slightly longer than those of controls, but the difference was not statistically significant. There is no mention of weight and food intake.

In the 1945 study, male and female Wistar rats were put on various versions of intermittent fasting. The rats fasted either one day in four, one day in three, or every other day. Fasting was begun at the age of 42 days and was continued until the rats died.

With the exception of females fasted once every four days, the average lifespans of all fasted rats exceeded that of the controls. The increase in lifespan was slightly greater in males than in females, although females still outlived males in general. In male rats, the most effective method was fasting every other day, while in females fasting once every three days gave the best results on average. However, both the male and female rat that lived the longest (1057 and 1073 days, respectively) were fasted every other day.

Food intake was not measured, but since the intermittently fasted rats weighed less than the control rats, we can assume that they also ate less. No drastic retardation of growth was seen, however. So, the first available study on intermittent fasting shows that when rats are intermittently fasted, they don't compensate for all the missed calories on the ad libitum days, and thus are CR'd, and therefore live longer. No big surprise there.

After this study, there was a gap of four decades before similar experiments were done again. During the 80's and 90's, three papers on intermittent fasting and lifespan were published by the same team. In the first one, male Wistar rats were fed either ad libitum or every other day since weaning (link). The mean lifespan of the fasted rats was 83% greater than that of the control group. And, just like in the 1945 study, fasting resulted in a lower body weight. The abstract doesn't mention the exact weights, but since the fasted rats took 75% longer to become fully grown, it looks like they ended up eating significantly less.

In the second paper, male Wistar rats were again fed ad libitum or every other day since weaning (link). This time they were also allowed voluntary exercise. The fasted rats exercised less in their youth but more when they were older. They also lived longer and weighed less than the control rats. However, in contrast to the first study, their growth duration was the same while growth rate decreased. That is, it looks like in the first study both groups eventually grew to the same size, while in the second study the IF rats remained smaller.

The third paper looked at the longevity effect of intermittent fasting (every other day) on three strains of mice, beginning at various ages (link). In two of the strains, mean and maximum lifespan increased and body weight decreased. The A/J strain, on the other hand, showed different results. When intermittent fasting was begun at 1.5 months, the mice lived longer despite not weighing less. When it was begun at 10 months, they again weighed the same as controls but actually died earlier. The rats that began fasting at 6 months weighed less than controls at some ages but showed no difference in lifespan.

Conclusion

In summary, it looks like intermittent fasting extends lifespan in rats and mice only when it is accompanied by calorie restriction. It does not mean that the animals are also put on CR; rather, they just naturally end up eating less (unlike humans, who tend to be very flexible and good at compensating for calories). And, in the rare cases that the animals actually do eat twice as much the next day, their lifespans are not increased.

For those who are doing IF for other reasons than life extension – such as improving insulin sensitivity or ">weight loss – this is not necessarily a concern. While some of the other health benefits reported in the studies are probably a result of calorie restriction, just like lifespan increases, I suspect IF even without CR still has some benefits in humans. It's just that based on the rodent studies, those benefits won't be enough to make us live longer.

For more information on diet and longevity, see these posts:

Dietary Supplement Increases Lifespan by 11% in Healthy Mice
Slowing Down Aging with Intermittent Protein Restriction
How to Live Forever: My 5 Steps to Immortality
Intermittent Fasting Reduces Mitochondrial Damage and Lymphoma Incidence in Aged Mice

I had a lot to say...

...but didn't say it. At least not here.

I haven't been much of blogger lately. I've had more than a few other things with which to keep myself occupied.

However, I was going to blog regularly while I was on my trip to the Dominican Republic. I did a good job the first night. I wrote out by hand some great notes the second and third day and then never got them online, and, well, that's that. I just never got back to it.

But, I find there is some value in this kind of informal writing. Writing is writing. And writing of any kind, whether in a journal, the back of a napkin, or on a blog, is good for a writer. So I may be back on here from time to time.

My Current Health Regimen v2.0

One of the changes has been an increased intake of fruit and vegetables. (Photo by YimHafiz)

This is my updated health regimen, aimed at adding a significant number of healthy years to my expected lifespan. As it's subject to change, I will keep this post updated accordingly. Major revisions (such as v2.0) will appear once a year or so; minor changes (such as v2.1) will be made as needed. With every major revision, I will move the post from the archives to the front page.

Since a long, healthy life is preferable to a short life by most people, following the regimen would make sense even without considering technological innovations. The true goal of my regimen, however, is to stay alive long enough to see rejuvenation therapies become a reality. In the long run, each year that I'm able to add to my expected lifespan now through things like dietary changes, exercise, and supplements, may grant me several extra years in the future.

Therefore, even those lifestyle changes that require considerable effort and resources while offering a seemingly limited benefit, make sense if one looks at the big picture. For a chance to see the world in 2090, I'm willing to skip the cheeseburger today.

My health regimen consists of four categories: diet, supplements, physical exercise, and brain health. All of the items under each category have some kind of scientific basis, and in contrast to my ongoing experiments, will remain a part of the regimen for the time being. Therefore, my current experiments are not a part of my long-term health regimen – unless they prove to be beneficial, in which case they'll be moved from ongoing experiments to the regimen.

Main changes from v1.0: none.

Avoiding harmful foods

The most important part of my diet is avoiding unhealthy things; increasing the intake of healthy things only comes in second. This is because preventing damage from happening in the first place is easier than repairing it later on.

I consider the worst culprit of modern diets to be an emphasis on grain products, fructose, and polyunsaturated fatty acids. There's considerable evidence to suggest that most people would do much better without them. Hence, things like pasta, rice, bread, candy, fruit juices, and most vegetable oils are off the daily menu. I only eat them rarely, and then simply because they taste good. For the past few months, I've allowed myself to eat whatever I want once a week (usually foods like pizza or fresh bread), which seems to be working well.

I originally cut back on my fruit intake, which used to be quite high some years ago, because I learned that fructose increases triglycerides especially in men, and fructose is not handled very well by the body in general. I later learned that fructose also forms AGEs much more rapidly than glucose, which kept me from reintroducing most fruits to my diet and eat berries instead, since they contain more nutrients per fructose calorie. However, I've now increased even my fruit intake a little, having read more about the AGE-inhibiting effects of phytonutrients found in fruit. I will expand on this later, but for an example of what I'm talking about, see my post about carotenoids inhibiting lipid peroxidation.

While much of this fits well with paleo dieting, I also diverge from the paleo diet these days. You may or may not remember that I used to be a potato hater back in the day, both because they could not be eaten raw (making them anti-paleolithic) and because of their high carb content. Basically, potatoes are just empty calories. But once you have your insulin sensitivity and blood glucose under control, I don't think a few potatoes now and then is much of a concern. At least they're low in fructose.

As you may recall, I followed a low-carb diet for the past year with an emphasis on paleo foods. I got on the low-carb, high-fat wagon in the first place to prove that eating a diet high in fat does not make you fat – and it didn't. However, this diet combined with my year-long intermittent fasting experiment resulted in a moderate-to-high intake of protein, the longevity effect of which I'm now questioning. To lower my protein intake slightly means eating either more fat or more carbohydrates, and since my fat intake is already very high, I've reintroduced some carbs into my diet. That is, I now occasionally eat potatoes not because I think they are necessary for health, but because they are low in protein. More on protein and longevity in future posts.

I still don't make nuts a dietary staple, because of their poor omega-3/omega-6 ratio and because I like to keep my PUFA intake low. That is, I aim not only for a good ratio of omega-3 and omega-6 fatty acids, I try not to eat too much of them in general. Omega-3 is particularly prone to undergo lipid peroxidation, and while nuts probably have micronutrients that protect them from oxidation to some degree, I'm playing it safe until I learn more.

Main changes from v1.0: slightly increased carb intake, slightly decreased protein intake, slightly decreased polyunsaturated fatty acid intake.

Eating healthy foods

Despite eating some more carbs these days, my diet is still fairly low in carbohydrates. My daily intake used to be around 100 grams; I have not measured my current intake, but I suspect it's around 100-150 grams these days. My main protein sources used to be meat, fish and eggs, but during the past year I've cut back on eating eggs because of their high methionine content. I'm still figuring out whether methionine restriction makes sense in humans, but in the meantime I limit my egg intake to 3-4 eggs a week.

Sources of fat, in the order of importance, are olive oil, palm oil, butter, cocoa butter, coconut milk, ghee, coconut oil, and sesame oil. Olive oil tops the list because I love the taste and because it's high in MUFAs but low in PUFAs and consistently does well in just about every health study. There may not be anything magical about MUFAs per se, but even if it's the polyphenols in olive oil that are behind all the positive health effects, olive oil still seems like a good choice. Palm oil is there because it's rich in tocotrienols (at least compared to other natural foods), low in PUFAs and high in SAs (making it suitable for heating), and because I've grown to like the taste.

Lard is off the menu for now because I ran out. Heavy cream has been replaced by coconut milk, partly because of dairy products increasing IGF-1, which may be bad for longevity (more on that in future posts). I don't eat cocoa butter raw (although I could, it's delicious), but I get plenty from all the dark chocolate I eat. Somebody asked me in the comment section why I eat sesame oil since it contains quite a bit of PUFAs, and noticing this was indeed so, I was going to remove it from my diet altogether. However, doing some reading I found that sesame oil seems to reduce markers of lipid peroxidation, so I kept it on the menu. I just use it for taste, however, so my intake of sesame oil is very low anyway.

Depending on my daily menu, anywhere between 50 to 70% of my total calorie intake is from fat. My daily menu has changed a bit, but percentage of fat is still the same. Most of this is saturated fat, which has been given a bad rep for reasons I believe are incorrect. I began reducing grain products and increasing my saturated fat intake years ago, and it hasn't killed me yet. In fact, my HDL has increased and my LDL has decreased on this diet. Triglycerides are not bad but could be better – a testament to my main vices, beer and wine.

There is one cereal grain I regularly eat, however: rolled oats. They're a convenient source of beta-glucan, which appears to be good for cholesterol and avoiding heart disease, and they don't contain gluten. Oats also contain quite a bit of quality protein. I used to eat them with milk and berries, but then switched to a combination of heavy cream and water to reduce my consumption of lactose and galactose (which easily form advanced glycation endproducts, AGEs). Now, I've stopped adding even heavy cream, because milk protein seems to interfact with the polyphenols in berries. So it's a mixture of coconut milk and water nowadays – not as good as cold milk, but still pretty good.

As for red meat, despite how it's portrayed in the media these days, I'm not convinced that meat consumption is harmful. Indeed, a recent review supports the hypothesis that processed meat, not meat in itself, may be harmful. The biggest problem I used to see with meat is the generation of AGEs. Though there is disagreement just how harmful consuming AGEs with food are, I tried to minimize the potential damage by avoiding overcooking and taking supplements. I no longer think AGEs in meat are a huge problem, however – more on this later. The reason I don't eat huge portions of meat like I used to is because of the high protein content.

And finally, the beverage department. I still love my daily coffee, which I drink 1-2 cups per day. Coffee has some nice health benefits too. Green tea is obviously staying on the menu; the studies showing positive health effects just keep on piling up. All in all, beer doesn't really belong to the "eating healthy foods" category, but even beer does contain some good stuff.

As you may recall, I used to drink yerba mate with meals to reduce the formation of AGEs. It's since come to my attention that yerba mate is carcinogenic at higher doses, so I now drink it only rarely. Green tea or black tea are safer bets, despite somewhat contradictory results in reducing AGEs and ALEs.

Main changes from v1.0: decreased egg intake, changes in the use of fats and oils, reduced yerba mate consumption, avoidance of lipid peroxidation.

A note on diet tweaking

It's much easier to point out things that are wrong in various foods than it is to prove something is healthy. These days, I'm more wary of advertising my diet as the best choice for everyone than I was before. Part of the reason is that the more I read and learn about nutrition, the more complicated everything becomes.

Case in point: I used to tell people vegetables are bad because, as an evolutionary strategy, they produce toxins to protect them from being eaten (which is true). Now, having learned of the importance of hormesis, I think vegetables are good because of those same toxins! I was also a huge fan of eating fruit (especially organic fruit) at one point, because it seemed to make sense from an evolutionary point of view. The, I got a little skeptical towards them because of their fructose content. Now, I think the benefits may outweigh the negatives.

All this, however, doesn't stop me from wanting to find the optimal diet for longevity. On the contrary, it's a healthy reminder not to get too emotionally attached to my health regimen, and to be ready to admit mistakes and make alterations as I learn more.

Going without food

The third key component of my diet used to be intermittent fasting. I stated in the first version of this post that "I may change my mind in the future, but for now I expect periodic food deprivation to remain in the regimen." That is still true to some degree: I no longer do a 24/24 hour cycle of fasting and eating, but I don't make it a point to eat three meals with snacks a day either. I often skip breakfast and lunch and eat only dinner.

The thing that lured me to try intermittent fasting was that there are studies suggesting that all or most of the benefits of chronic calorie reduction can be had by alternating zero calories with double the normal calories every 24 hours. While I no longer believe that IF is equivalent to CR, I do think that fasting in general is beneficial. An improved insulin sensitivity is a known result of intermittent fasting. Insulin sensitivity is associated with longevity, and among supercentenarians, insulin sensitivity is common.

Perhaps a more interesting thing about fasting is that it increases autophagy, a process in which the cell consumes a part of itself for energy. This can happen during ordinary cell maintenance, or when the body is deprived of nutrients. Since improved autophagy is at least in part why caloric restriction works, this makes other, less demanding forms of nutrient deprivation attractive options.

The reason I stopped doing strict IF is because I don't think there is much evidence that fasting for 24 hours and then eating for 24 hours is somehow optimal in itself. Most importantly, IF does not extend lifespan in most studies. Why IF is not equivalent to CR is not clear, but recent studies suggest protein may have a lot to do with it. My intermittent fasting diet resulted in huge meals with lots of protein, and I now suspect that this may have diminished much of the potential benefits.

Main changes from v1.0: no more 24/24 intermittent fasting, no more huge protein-heavy meals.

Supplements

The most important supplement in my regimen is vitamin D3. Most people are deficient in vitamin D, and the health benefits are so overwhelming that if there's one supplement I would recommend spending money on, it's vitamin D3. I usually take 5,000 IU of vitamin D3 daily, and at last check, my levels were at 45 ng/mL, which is in the optimal range. Now that it's summer, I'm taking 2,500 IU daily. I know some people take the same amount all year round, but since I do spend some time in the sun, I don't want to overdo it.

One of the supplements that has remained in the regimen since last time is vitamin K2, which is sort of a newcomer in the supplement scene but nonetheless has some impressive studies behind it. I'll write more about it in the future, but here's one study of interest for men: dietary vitamin K2 may reduce prostate cancer. Since fermented dairy products, which I'm not sure are the best choice for health otherwise, are the best dietary source of vitamin K2, I'm taking supplements instead. At the moment, I take 90 mcg of MK-7 (Jarrow MK-7) and 5 mg of MK-4 (Carlson Labs Vitamin K2) every third day in an attempt to find a balance between affordability and the long serum half-life of vitamin K2.

I used to take a tablespoon of fish liver oil daily, because it has lots of omega-3 fatty acids in bioavailable form (EPA and DHA) and almost no omega-6 fatty acids. A higher dietary ratio of omega-3 to omega-6 seems to be very beneficial in general, and fish oil has been shown to decrease inflammation. A commonly quoted optimal ratio is between 1:1 and 1:4, which seems to be close to how our paleolithic ancestors ate. As part of my plan to avoid excess PUFAs, I've dropped fish liver oil from the menu. I'm currently in the process of weighing the pros and the cons; it may be that a tablespoon per day will prove to be worth it in the end.

I also used to take resveratrol with quercetin during fasts to increase autophagy. I would still continue to take them, but unfortunately I can't afford all the supplements I might like to take (including AOR Ortho-Core, which is off the list for the time being), so I take resveratrol only occasionally. Meanwhile, I'm on the lookout for other things that increase autophagy. Curcumin is a cheap alternative, and it has other health benefits too, which is why I add turmeric to most of my foods.

Since my damn blender keeps leaking from the bottom, I'm no longer making smoothies every day like I used to. So these days I just add some ground flax seeds to my rolled oats for the flax lignans. Flax lignans may prevent hair loss, among other health benefits. Some people prefer to take them in supplement form, but flaxmeal is a cheaper and equally effective way to consume flax lignans. For best effects, they should be consumed twice a day with ~12 hours in between. Other things I do to prevent hair loss is use shampoos with ketoconazole and piroctone olamine.

Main changes from v1.0: no more fish liver oil, some supplement cutbacks due to costs, increased curcumin intake.

Exercise

My exercise routine is probably the weakest part of my regimen, compared to how much effort I put into diet and supplements. In the summer, I run for 30-45 minutes once a week to get some aerobic exercise (I should start again, since summer is here!) The goal is to keep the heart and lungs healthy, reduce blood pressure, and improve mood. In the winter, when it gets too cold for running outside, I go to the gym for strength training instead. Strength training reduces the risk of injury, prevents osteoporosis, supports joint health, and prevents muscle loss resulting from aging.

I also practice martial arts, which combines aerobic and strength training, to a degree. The main reason for me, however, is that it provides me with a basic set of self-defense skills and improves coordination. With aging, there is usually an increased fear of falling and hurting oneself – something children naturally don't have. Getting thrown around every week is a way to maintain a healthier attitude towards my body and prevent an irrational fear of getting hurt. I want my mind to rule over my body, not the other way around.

Main changes from v1.0: none.

Brain training

Any anti-aging regime should also take into account the importance of maintaining mental health. It doesn't take a genius to see that people who use their brains actively retain their cognitive abilities far longer than those who are passive.

One of the ways I keep the rational side of my brain fit is reading scientific papers and writing about them on this blog. I like logical problems in general, and I think practicing problem-solving skills are important for everyone, whether it's through work or hobbies. To train the creative side, I do things like play instruments, compose music, and read and write fiction.

My biggest problem is and always has been rather poor short-term memory. I don't know whether it's because my mind is always occupied with a zillion things, but it's more than once that I've gone to the grocery store to buy something I need and come back with something else entirely. This kind of absent-mindedness seems to run in the family. I believe it can be improved through training, however. The memory game experiment intends to increase IQ, but it improves short-term memory as well (I've pretty much forgotten about this experiment lately, by the way – I'll have to start playing again!)

Main changes from v1.0: none.

Quick summary of the health regimen

As a part of my diet, I regularly eat the following foods:

- Meat, fish
- Olive oil, palm oil
- Butter
- Vegetables, berries, fruit, oats, dark chocolate, coconut milk
- Coffee, tea, wine, beer

I limit or avoid eating the following foods:

- Grain products like pasta, bread, and rice
- Fruit juices, candy
- Vegetable oils high in PUFAs

In general, my diet is high in fat and lowish in carbohydrates. I consume saturated fat and monounsaturated fat liberally but limit polyunsaturated fats.

My supplement regime consists of the following:

- Vitamin D3: 2,500-5,000 IU daily
- Vitamin K2: 90 mcg of MK-7 and 5 mg of MK-4 every third day
- Varying amounts of green tea daily
- Flax lignans: 1-2 tablespoons of ground flax seeds daily

My physical health regime consists of martial arts, running (in the summer), and strength training (in the winter). For mental health, I do things that train the creative and logical sides of the brain.

For more information on anti-aging methods and living longer, see these posts:

Anti-Aging in the Media: New York Times on Caloric Restriction and Resveratrol
How to Live Forever: My 5 Steps to Immortality
L-Carnitine, Acetyl-L-Carnitine and Cognitive Function in Humans
Caloric Restriction Improves Memory in the Elderly

BioSil, JarroSil & Beer – Silicon Experiment Conclusion

Beer – it's not just the alcohol that goes to your head. (Photo by Fabrice ROSE)

This post is the long overdue conclusion to my silicon experiment. The idea was to replicate a study that found improved skin quality, nail thickness and hair growth using a bioavailable form of silicon known as choline-stabilized orthosilicic acid (ch-OSA).

For two and a half months, I mixed five drops of Natrol's BioSil product with juice. This was equal to 5 mg of ch-OSA, which is only half the dose used in the original study. In an update post, I wrote that there might have been a slight increase in the thickness of my nails. I did not see an increase in the speed of growth, however. Hair growth and skin quality were also unchanged.

I then increased the dose to 10 mg for the next two months. To make the experiment more scientific, I began cutting my nails every 14 days to see if there was any change in how quickly they grew. Again, there was no significant change in skin, nail or hair quality.

After the bottle of BioSil was finished, I continued the experiment with Jarrow's JarroSil product while keeping the amount of orthosilicic acid at 10 mg. There's not much difference in price between the two products, but one thing Jarrow definitely has over Natrol's orthosilicic acid is the taste: BioSil tastes pretty horrible, while JarroSil doesn't really taste much of anything.

I now have several months of experimentation behind me with JarroSil. After a month or so of taking 10 mg daily, I began a routine where I take the product for two weeks and then have two weeks off, all the while keeping an eye on hair and nail growth and skin quality.

Even though I had pretty high expectations from ch-OSA, given that it had the science behind it and people seemed to have good experiences with it in general, I can't say I noticed any improvements. Hair thickness has not increased, at least not visibly, and my skin looks the same regardless of whether I'm using the product or not. On some weeks I think my nails grow faster than on others, but this seems to be independent of silicon.

One reason for not seeing any positive results may be that the original study was done on middle-aged women. Perhaps the benefits of orthosilicic acid supplementation come with age. Another possible explanation is that dietary intake of orthosilicic acid also plays a role. The European Food Safety Authority has estimated that the typical dietary intake of silicon is 20-50 mg. Maybe I already get enough bioavailable silicon from my diet, and the extra 10 mg did not yield any additional benefits.

Speaking of bioavailable silicon, did you know that the best dietary source is beer? According to one study, beer contains a little less than 20 mg of silicon per liter on average, regardless of the type or geographic origin of the beer (link). The actual amount varies between 9 and 39 mg per liter.

About 80% of the silicon is in the form of orthosilicic acid, which is the bioavailable form. The absorption of silicon from beer is 55%. This means that a can of beer (330 mL) contains, on average, about 7 mg of silicon. Of this, about 5.6 mg is orthosilicic acid, about 3.5 mg of which is absorbed.

There is no data directly comparing the bioavailability of ch-OSA and orthosilicic acid from beer, but since the urinary excretion rates of the two appear to be similar, we can assume their absorption is also similar. Thus, two cans of beer would give roughly the same amount of orthosilicic acid as used in the study.

Jarrow and Natrol mention only that silicon is poorly absorbed from many food sources and that orthosilicic acid is easily polymerized, which dramatically reduces its bioavailability (the choline is added to prevent the polymerization). This is indeed true, but they neglect to mention that not all dietary sources of silicon are poor. Beer seems to be the best one, but even water and mineral water contain 2-5 mg of orthosilicic acid per liter (link).

Since beer is one of my vices, I think I get enough orthosilicic acid in my diet anyway, so I won't be investing into supplemental forms anymore. However, if your dietary intake is low and you're looking for ways to increase hair or nail thickness, supplementing with JarroSil or BioSil may be worth a shot.

Even though my conclusion to the experiment is that I did not notice any visible results, I'm not disregarding orthosilicic acid as worthless. In fact, a new study confirms some of the findings of the study on photoaged women (link):

Forty-eight women with fine hair were given 10 mg Si/day in the form of ch-OSA beadlets (n = 24) or a placebo (n = 24), orally for 9 months. Oral intake of ch-OSA had a positive effect on tensile strength including elasticity and break load and resulted in thicker hair.

It may be that some of the effects are more preventative rather than visible improvements. In the above study, for example, the increased thickness was in comparison to the placebo group, not the beginning of the experiment. Both groups saw decreases in hair strength; the supplemented group simply experienced a smaller decrease.

The next time someone argues that drinking is bad for the skin, you can counter them with the high silicon content of beer.

For more information on hair and skin, see these posts:

The Forgotten Anti-Aging Classic: Retinoids Are the Skin's Best Friend
Topical Vitamin C for Skin: Re-examining the Case
Lutein for Skin Elasticity, Hydration and Photo-Protection – Experiment Begins
Coconut Oil Is Better than Olive Oil for Atopic Dermatitis