Monday, September 29, 2008

How Does Fructose Affect Triglyceride and Cholesterol Levels?

Not all sugar is created equal. (Photo by anyjazz65)

Compared to glucose, which sounds like something extracted and processed in some dull laboratory, fructose has a nice ring to it: You instantly think of bundles of fresh fruit or a refreshing glass of fruit juice. Those couldn't possible be anything but healthy, could they? It's the glucose that is the bad sugar, right?

Well, not exactly. Excess sugar in general is bad for you, but there are differences between fructose and glucose, and not all of them are in favour of the former. Spesifically, it is the effect of fructose on triglycerides that is of most concern. In this post, I review some of the research on sugars, cholesterol and triglycerides.

Studies on rats

This rat study from 2000 compared the effects of different carbohydrate sources on blood triglycerides, total cholesterol and HDL cholesterol. The rats were either given a free or 60% restricted access to one of the sources (cornstarch, sucrose, glucose, fructose or a fructose-glucose mix), so the study effectively compared both a calorie-restricted version and an ad-lib version of all five diets. The authors conclude that the source of dietary carbohydrate did not have a significant effect on body composition or cholesterol but did increase serum triglyceride in the fructose group - both in the CR and the ad-lib fed rats.

Unsurprisingly, the calorie-restricted rats lived longer than their peers. What is interesting is that while the source of carbohydrate did not affect the lifespans in the ad-lib groups, the calorie-restricted fructose group actually lived longer than other CR groups.

In a newer study from 2008, rats were fed a 63% glucose or fructose diet for two weeks and then killed either after feeding or after a 24-hour fast. The authors conclude that fructose feeding induced a broader range of genes than previously identified and also increased triglycerides in the liver when rats were killed after feeding. In rats killed after the fast liver triglycerides were lower, however, but plasma triglycerides were higher.

Studies on humans

The more interesting part are obviously the human studies, of which there thankfully are quite many. The sugar-sweetened beverage and 100% fruit juice consumption of children and adolescents in the United States today is about 270 kcal per day, up from 242 kcal/day in 1988-1994. An increase of less than 30 kcal is not as great as one might have guessed, but the total amount is still 10-15% of total calorie intake, which is quite a lot, and the percentage has increased in the past few decades.

In this study from 2000, a subject group of 12 men and 12 women was given either a diet providing 17% of energy as fructose or a diet using glucose instead. Both diets lasted for six weeks. In men, the fructose diet produced significantly higher (as high as 32%) triglyceride levels than the glucose diet. In women, there was no difference. No effect was observed for cholesterol levels in either men or women.

In this recent study from 2008, 4 men and 2 women consumed either glucose, a 50:50 mixture of glucose and fructose, or a 25:75 mix of glucose and fructose in the morning. Higher fructose consumption stimulated lipogenesis, which is the process of simple sugars being converted into fatty acids, eventually forming triglycerides. Unfortunately, the sample size is quite small and the experiments were apparently done only once.

Another study from 2008 compared the effects of fructose in healthy males and females. The subjects were fed fructose (the abstract doesn't say how much) for 6 days, which increased serum triglycerides by 71% in men and 16% in women. Fasting insulin increased by 14% in men, but did not significantly increase in women.

Authors of this study from 2008 came to a different conclusion: It found no increase in triglyceride levels after a diet with fructose accounting for either 6% or 24% of total energy intake. Again, the sample size was small (six persons) and the diets lasted only a week.


Though not all researchers agree, it seems likely that fructose has a negative effect on triglyceride levels, at least in men.
Why the effect is not seen or is smaller in women is not clear. Cholesterol, on the other, is unaffected in both men and women.

Fresh fruits certainly have their benefits - not to mention they taste good - but they have their downsides as well. Fruit juices especially are high in fructose, so just because something says "no added sugar" or "100% fruit juice" does not necessarily mean it should be drunk in gallons. Personally, I still consume fruit juices every now and then, but try to limit the amount and choose juices made from fruits that are lower in fructose (such as grapefruit).

For more information on cholesterol and triglycerides, see this post:

Coconut Lowers LDL, VLDL and Triglycerides, Raises HDL

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Saturday, September 27, 2008

Coenzyme Q10, Exercise and Oxidative Stress

Coenzyme Q10 and exercise
The relationship between athletic performance and CoQ10 is still unclear. (Photo by foxypar4)

I've been taking 200 mg of CoQ10 (also known as ubiquinone) daily for more than two months now to see whether it has an effect on general health and exercise performance. While I haven't noticed much of a change, I've ran across some interesting information regarding coenzyme Q10 that I thought would be useful to share.

First off, there is a lot of anecdotal evidence on the benefits of using ubiquinone while doing strength training or aerobic exercise, but actual studies on the subject are rather inconclusive. In a 1997 study on Finnish cross-country skiers, 94% of the subjects reported improvements in performance and recovery time vs. only 33% with placebo. Measures of physical performance also improved significantly. The amount of coenzyme Q10 used was 90 mg per day.

In another study from the same year, male road cyclists and thriathletes were either given CoQ10 or a placebo. In the former group, plasma concentrations of CoQ10 increased significantly, but this had no significant effect on measures such as oxygen uptake, heart rate, and blood pressure. The amount used was 1 mg per kg of body weight, which is probably slightly less than in the other study.

In yet another study from 1997, 18 subjects were given either CoQ10 or a placebo. During running, there were no significant differences between the groups, but strangely, on a high intensity anaerobic cycling test, the placebo group actually did better. There is no mention of the amount used in the abstract.

In a study from 2005, six volunteers were first given a placebo, then 150 mg of CoQ10, then 150 mg of CoQ10 and 1,000 IU of vitamin E, and finally a placebo again. Plasma levels of CoQ10 increased slightly following supplementation, but muscle concentrations of CoQ10 or other measures showed no significant changes. There were no differences between the groups on a cycle test.

In a newer study from 2008, aerobically trained and untrained men and women were given either 100 mg CoQ10 or a placebo twice daily (yielding a total of 200 mg per day). CoQ10 supplementation resulted in higher muscle CoQ10 concentration, lower serum superoxide dismutase (SOD) oxidative stress, and higher serum malondialdehyde (MDA). In general, CoQ10 increased time to exhaustion on a treadmill.

One more study from 2008 concludes that oral administration of CoQ10 improved subjective fatique sensation and physical performance during workload trials. The subjects were given either a placebo, 100 mg of CoQ10 or 300 mg of CoQ10. Apparently there was no difference with the lower dosage compared to placebo, but 300 mg showed significant benefits.

So what does this all mean? It's difficult to draw conclusions, but two things that should be paid attention to when interpreting these studies are the dosage used and the time of ingestion. The Finnish cross-country skier study showed benefits with only 90 mg per day, but on the other hand, in the 2005 study with six volunteers, 150 mg per day had no effect. It's interesting to note that in the last study I mentioned, effects were visible only at the higher dose of 300 mg per day.

The time of ingestion is important because coenzyme Q10 also functions as an antioxidant, whereas exercise increases oxidative stress. The free radicals generated by exercise are neutralized by an antioxidant response from the body. Regular exercise thus enhances the antioxidant defense system and protects the body from free radical damage.

The relationship between exercise and antioxidant supplements is not entirely clear, but it has been suggested that ingesting antioxidants right before or after exercise negates some of the beneficial effects of exercise. Put simply, the theory is that when the body gets the antioxidants through supplementation, the body's own response to oxidative stress is negatively affected. This may be part of the reason why some studies show positive effects from CoQ10 and others don't.

Unfortunately, there is little information available on this subject, and spesific time intervals between exercise and antioxidant supplementation are hard to define. Nevertheless, it may be wise to not take any antioxidants a few hours before and after exercise. So far, I've been taking CoQ10 every morning, but from now on, I'll take it in the evening on days of exercise to see whether it makes a difference - and just to be sure I'm not missing out on the benefits.

For more information on coenzyme Q10, see these posts:

Coenzyme Q10 for Exercise & Better Health - Experiment Conclusion
The Role of Coenzyme Q10 in Oral Health
How to Choose Between Different Forms of Coenzyme Q10: Ubiquinone vs. Ubiquinol

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Tuesday, September 23, 2008

The Psychological Effects of Intermittent Fasting

Hunger doesn't have to be a negative experience. (Photo by SuperFantastic)

I've noticed recently that whenever I tell people I'm doing intermittent fasting, at first they're usually very interested in why and how I do it. After explaining the details, however, they suddenly get very defensive and start coming up with reasons for not fasting themselves - even though I'm in no way trying to promote fasting. I'm simply stating my personal reasons for doing it, and though I believe the health benefits are universal, I'm not suggesting others should do it.

This psychological phenomena is interesting, and I feel it's not only applicable to intermittent fasting but to other things related to health and lifestyle as well. When you tell people that you've done changes that can be perceived as radical (even though they might not be so radical) and that require some effort, people often start rationalizing why they couldn't implement the same changes in their own life even if they wanted to. Thus, the reasons are more on the lines of "I can not do x because of y" than "I don't want to do x because I enjoy y more".

To me, this has always seemed like a strange approach. Why do so many people feel the need to have any other reason for doing or not doing things than personal enjoyment? It is a perfectly valid reason, after all. For example, I'm aware that caloric restriction is most likely superior to intermittent fasting in terms of longevity, but still choose not to do it because, well, it really is a hassle (read about my week-long experiment with CR here).

The most common objection to intermittent fasting I hear is that "my body simply couldn't cope with it", as if it were something only a small fraction of people could reasonably do. People say they need to eat regularly or else they will feel "tired" and "irritated", which apparently is a result of low blood sugar. Certainly blood sugar can have that kind of an effect, but who says it's a permanent one? The body is quite good at adapting to different kinds of environment, and as far as I know, there is no genetic reason why anyone in normal health could not go without food for at least 24 hours.

If you're used to eating three square meals a day, a good tip is to get into intermittent fasting slowly by shortening the eating window from one end little by little. For example, if you normally eat from 8 AM to 11 PM, try eating from 9 AM to 11 PM (or 8 AM to 10 PM), then 10 AM 11 9 PM (or 8 AM to 9 PM), and so on. This way your body will get used to being without food for longer periods of time. When you feel comfortable with it, you can switch to using cut-off points (i.e. eating from 6 PM one day to 6 PM the next day, or whatever you think is the best time of day to either start or stop eating).

Another tip is to mentally associate the feeling of hunger with good things instead of bad things. When you feel like eating, don't think of it as some kind of a emergency signal that must be obeyed blindly but as a sign that something good is happening inside your body - that you are in fact experiencing the health benefits of intermittent fasting. We're not talking about starving here. Hunger will not kill you.

There's some controversy over whether caloric restriction affects mood negative or positively, and while intermittent fasting is not exactly the same thing, they do share many of the same benefits. This study reports that when your body notices it needs more calories, levels of a hormone called ghrelin increase. Ghrelin is known to trigger hunger, but the researchers discovered that its main function is to reduce stress. Mice with low ghrelin levels seemed depressed, while mice with high ghrelin levels were more social and energetic.

It's difficult to say how significantly intermittent fasting by itself has affected my mood, but I definitely haven't experienced anything negative so far. Granted, sometimes when I get really hungry during a fast, I feel fatiqued, but it is more a physical effect than a psychological one - the fatique is not accompanied by depression. And quite often fasting seems to give me a very energetic and happy mood, which has been one of the best parts of this experiment.

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Thursday, September 18, 2008

Controlling Hunger During a Fast: Does Decaffeinated Tea Help?

Decaffeinated tea and fasting
Decaffeinating tea results in less catechins. (Photo by qmnonic)

Previously in my quest for zero-calorie appetite-suppressing liquids to help me with intermittent fasting, I have tested green tea, black tea and coffee. Coffee has been the most effective, followed by black tea and finally green tea. This order suggests that the key ingredient is caffeine, because green tea has the least caffeine and coffee has the most.

In order to find out how much of the effect is in fact due to the caffeine content, I purchased decaffeinated black tea, which I've been consuming during the past week or so. The results confirm the caffeine hypothesis: decaffeinated tea is no more helpful in controlling hunger than, say, water. Obviously drinking any liquid has the potential to mask the feeling of hunger for a short while, but the difference between normal black tea and decaffeinated black tea is quite noticeable.

The only use I can find for decaffeinated black tea is for drinking it in the evening, when large amounts of caffeine is a bad idea - for me at least. Other than that, normal black tea or green tea is the way to go, because the decaffeination process also affects the polyphenol content of the tea, so you'll be missing out on some of the positive health effects of tea.

For more information on green tea, black tea and fasting, see these posts:

The Psychological Effects of Intermittent Fasting
Dental Health Effects of Green and Black Tea
Green Tea Reduces the Formation of AGEs
Black Tea Is More Effective in Activating Superoxide Dismutase (SOD) than Green Tea

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Monday, September 8, 2008

Controlling Hunger During a Fast: Does Coffee Help?

Coffee and fasting
Coffee has more caffeine than black or green tea. (Photo by alex-s)

In my previous post on the subject, I mentioned I would buy decaffeinated green tea to see how much of the appetite-reducing effects were due to the caffeine content of green tea. Unfortunately, the only thing I was able to find is decaffeinated black tea (which was ridiculously expensive, by the way). I haven't got around to really experimenting with it yet, so for the past week I've been drinking coffee instead.

My experiences with coffee suggest that caffeine is a big contributor in the reduced hunger effect. A rather modest amount of coffee will do the trick for me, whereas several cups of tea are needed to really see the benefits. This would fit in well with the fact that coffee contains more caffeine than tea.

Coffee seems to be especially useful in the morning, when just one cup is enough to suppress appetite, boost mood, increase energy and improve concentration. It is also helpful with what I call psychological hunger: when I smell all those delicious freshly baked bagels and sandwiches and see other people having their breakfast, the smell and taste of coffee alone is enough to keep me from breaking my fast. It's almost like cheating the brain to make it think I've eaten breakfast as well.

The same problems I have with drinking tea later during the day are apparent with coffee, too. Near the end of one fast, I drank a very large mug of coffee to see what happens. At first, I noticed a considerable reduction in the feeling of hunger and a slight increase in energy. However, it quickly turned into a nauseous feeling, fatique, and lack of concentration. I also noticed my hands were shaking quite a bit. As noted earlier, there was a similar (though not as strong) an effect with black tea, which has more caffeine than green tea but less than coffee. Again, this fits well with the caffeine hypothesis.

What surprised me somewhat was that so far, coffee has given the best results - when consumed in moderation. I'm a big fan of tea, but when it comes to improving concentration and getting an energy boost, coffee is definitely the winner. It really does help to kick things off in the morning. One small cup is enough for me, though, and in the afternoon it looks like I might have to stick to one or two cups of tea to avoid the negative effects.

For more information on tea, coffee and intermittent fasting, see these posts:

Controlling Hunger During a Fast: Does Decaffeinated Tea Help?
The Psychological Effects of Intermittent Fasting
Dental Health Effects of Green and Black Tea
Green Tea Reduces the Formation of AGEs

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Thursday, September 4, 2008

MSM + Chondroitin + Glucosamine for Hair & Nail Growth - Results after Seven Weeks

MSM powder has a nasty sulfuric taste. (Photo by Shiny Things)

For the past seven weeks or so, I've been supplementing with a powder containing 1,000 mg of methylsulfonylmethane, 600 mg of glucosamine and 400 mg of chondroitin per teaspoon. The idea was to see whether has other interesting qualities - namely, an effect on hair and nail growth - besides the horrible sulfuric taste.

If you Google "MSM hair growth", you're bound to find dozens of anecdotal claims of MSM's efficiency. My personal experience, however, has been a disappointment. I haven't noticed any difference in the rate of growth of my hair and nails, and definitely not in the strength.

The one study that exists on this subject concluded that 3,000 mg of MSM had a notable effect on the subjects. Thus far, I've been taking only 1,000 mg per day, which might of course be too small an amount to affect anything.

To see whether a larger dosage makes any difference, I'm going to start taking more MSM (and maybe skip the glucosamine and chondroitin). I'll just have to locate a product that is decently priced first - the previous one I tested was too expensive to take in quantities larger than one teaspoon per day. Capsule form would be nice, too, so I wouldn't have to deal with the unpleasant taste of the powder.

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