In today's world, the latest medical findings are broadcast everywhere. We see the same stories on TV, in magazines, in newspapers, and on the Internet.
That means most of us are aware of medical findings about healthy living. We know that omega-3 fatty acids from fish are healthy. We know that trans fats are bad for us. We know that salt isn't good for us. We know that LDL cholesterol is bad for us. We know that skim milk is better for weight loss. And we know that losing weight will help us live longer.
But what if all these ideas were wrong?
Research reported recently has suggested this might be true, at least in some cases. And one researcher has gone as far as to suggest that 90% of the research doctors and patients rely on is "flawed." That doesn't mean it's totally wrong. In some cases it might be. In others just not as perfect as we'd like it to be.
The recent studies that seemed to show something contrary to expectation included one study that showed that the omega-3 fatty acids in fish increase rates of a rare but aggressive form of prostate cancer, and trans fats reduce the risk.
The researchers agreed that omega-3s are beneficial in reducing the risk of heart disease. Many studies including one in Alaskan Yu'pik Eskimos have shown this. Obese Eskimos who had high levels of omega-3 fatty acids seemed to be protected from the inflammation and diabetes that often accompany obesity.
In the prostate cancer study, neither the omega-3s nor trans fats seemed to affect the risk of low-grade prostate cancers, and omega-6 fatty acid levels (found in vegetable oils) were not linked to any form of prostate cancer.
But men with the highest levels of the omega-3 fatty acid DHA had 2.5 times the risk of developing aggressive, high-grade prostate cancer compared with men with the lowest DHA levels. And men with the highest blood levels of trans fatty acids had a 50% reduction in the risk of the same cancer.
One could explain the results in many ways. The researchers measured the levels of the fatty acids in the blood. Perhaps the aggressive cancers altered the concentration of fatty acids in the blood, rather than vice versa. Most of the men got their omega-3 fatty acids from fish, not capsules. Perhaps the fish they ate were contaminated with pesticides that had a greater impact on the aggressive cancer than on other cancers.
So we really can't know for sure what this study means except the standard caveat, "More studies are needed."
Several studies have suggested that salt isn't the devil it's made out to be. The results of one study, which showed that the less salt people ate, the more likely they were to die from heart disease, were so surprising that officials at the Centers for Disease Control and Prevention publicly criticized the study, as reported in the New York Times. There were several reasons to question the statistics, and other people have shown that lower salt intake not only reduces blood pressure on average but reduced heart disease mortality.
So again. What do these results really mean?
It seems to me that because most people like salt, those who were trying to limit salt intake might be those who were worried about heart disease, perhaps because they had close relatives with heart disease and hence knew they were at higher risk.
However, another study, this one in patients with type 2 diabetes, also showed fewer deaths from any cause in the patients who excreted less sodium (and hence ate less, as sodium excretion is related to sodium ingestion), and the relation between salt intake and cardiovascular deaths was also statistically significant. Other studies (cited in the type 2 article) have shown no effect, a positive effect, or a negative effect of salt intake on mortality. But many of these studies relied on patients' recall of what they'd eaten recently, which is notoriously inaccurate.
Another recent study claimed that LDL, the "bad cholesterol" might not be all bad. After "fairly vigorous" exercise, those who gained the most muscle mass also had the highest LDL levels. Gaining muscle mass is good if you have diabetes, because the muscle takes up the most glucose from the blood.
A study in childen showed that switching to low-fat dairy foods resulted in lower saturated fat consumption, but no change in calories consumed, body mass index, or waist circumference. The children drinking low-fat milk simply ate more calories as carbohydrate. Not good when you have diabetes.
Finally, a recent study showed that mice who remained fat on a restricted calorie diet lived longer than those who lost weight on the diet. Note that this was a mouse study. Mouse results do not always translate into human results. Nevertheless, it might provide encouragement to people who can't seem to lose weight no matter what they do.
"Individuals who have difficulty losing weight may benefit from the positive effects of dietary restriction more than those who lose weight easily," said the senior author of the study.
One interesting thing about the results of the study is the comment that "there is nothing that works for every genotype." We patients on the Internet have known this for years. We call it "Your Mileage May Vary," or YMMV. It's nice that the scientists are beginning to accept this concept rather than scolding us when we don't lose weight on a diet that worked for someone else.
So what do all these seemingly contradictory results mean for us? Should we stop following our doctors' advice and just eat what we want and lounge around instead of getting exercise?
We should never change our lifestyle on the basis of just one study. If 25 studies have shown that eating tadpoles protects us from heart disease and one study comes out claiming that eating tadpoles causes heart attacks, of course we should pay attention. But unless we have access to all the procedures (not everything is mentioned in the Methods of complex studies) and statistical analyses used by all the authors, we really can't tell which of the studies is the most accurate. Unless the authors who claim that eating tadpoles is bad have a good reason that all the previous studies were wrong, the odds are in favor of the 25 studies that had the same result.
But I also think this uncertainty about the health advice we get suggests that moderation may be a good thing. Eat fish, or take fish oil capsules if you want, but don't eat fish 21 times a week and don't take 5 times the amount of fish oil recommended on the bottle. Try not to go overboard with the salt, but don't try to live a salt-free life. Most people get most of their salt in processed foods, including bread, and if you're not eating processed foods, you probably won't be eating a lot of salt. A shake or two here and there should be OK.
Try to limit your overall food intake, but don't starve yourself. If you're not losing weight despite limiting your diet, don't beat yourself up about it. Take a few supplements if you think your limited diet means you're not getting enough vitamins and minerals. But don't take megadoses. We never know what else is in those capsules.
Above all, enjoy life. David Mendosa is a good role model in this area. He's traveling a lot, hiking a lot, taking beautiful nature photos, and enjoying every day. Diabetes hasn't kept him down. It's improved his life!
Published On: May 17, 2011