No matter what kind of health system we end up with, we will increasingly be asked to take better care of ourselves. It’s fine to tell people to watch what they eat, but what if the advice we are given on how to do this is wrong?
Take saturated fat, for instance. For decades, we have been told to lower our intake of cholesterol and saturated fat, the kind found in dairy, eggs and beef. Doing so, we have been told, will not only make us slimmer, but will reduce our LDL or so-called "bad cholesterol" and risk of heart disease.
This advice can be found in official dietary guidelines and on nutrition pamphlets and is the reason for millions of dollars spent on so-called "low-fat" and "heart-healthy" foods, not to mention cholesterol-lowering drugs. But at best, it is an oversimplification. At worst, it may actually be making us fatter and in greater danger of getting heart disease.
LDL cholesterol is no single entity. As I reported in a large story in the February issue of Men's Health, it is an umbrella term for seven or so LDL subtypes, particles which rise or fall in our bloodstream differently in relation to foods, and which have differing relationships to heart disease. For example, according to Ronald Krauss, a lipid scientist at the University of California at Berkeley, saturated fat from dairy raises the largest forms of LDL, which are largely benign when it comes to heart disease.
Small forms of LDL, on the other hand, have a strong relationship to heart disease. Care to guess what foods cause an increase in small LDL? If you guessed refined carbohydrates, you get a free quart of heart healthy whole milk. Ironically, the corn-derived fillers found in many low-fat dairy products are just one example of refined carbohydrates in the food supply. But so are the starches and refined grains found in nearly every processed food.
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Your typical blood check can’t tell whether you have mostly safer forms of LDL or mostly dangerous forms of LDL. That said, a high LDL count generally reflects the presence of the safer kind increased by dairy fat, simply because the cholesterol inside the particles are big. Some Mayo scientists are promoting ways to count LDL particles more accurately by their shells. Other scientists, like Krauss, have developed – and profit from — small LDL-counting methods. But a troubling problem remains: in general, the LDL we measure during our annual check-up is a sloppy gauge of our risk of getting heart disease.
Krauss has received funding from the dairy industry, which would ordinarily make his defense of dairy fat suspect. But last January, he reported something in the American Journal of Clinical Nutrition that calls into question the demonization of all forms of saturated fat. After looking at 21 studies measuring the health of 347,000 people — and taking into account the foods used to replace saturated fat in the diet — he discovered "there is no significant evidence for concluding that dietary saturated fat is associated with an increased risk of (coronary heart disease) or (cardiovascular disease)." Earlier this month, a large analysis in the journal Circulation found that red meat does not increase your risk of heart disease either, as long as it is not processed.
If saturated fat doesn’t give us heart disease, what does that mean for how we should eat? Since small LDL – the dangerous kind — go up as HDL or "good cholesterol goes down, we should stay away from the two foods we know can reduce HDL: refined carbohydrates and trans fats. As a general rule, that means we need to eat more whole foods and fewer commercially prepared foods. Instead of crackers, we should hand our children cheese. Instead of juice or "low-fat" chocolate milk, we should give them 2 percent or whole milk.
That's just the takeaway for diet. As a society, the oversimplificaton of LDL is breaking our bank. It drives doctors to tell people to take statins, which costs American taxpayers billions of dollars each year thanks to their use by elderly people on Medicare. Statins do help reduce heart disease, but not as much as we think and very likely for reasons that have less to do with lowering LDL than with other effects of the drugs.
Finally, if saturated fat does not give us heart disease, does it still make us fat? Fat is dense in calories, but it is a better calorie than one consumed from a refined carbohydrate. (All calories are not the same, as Gary Taubes exhaustively explains in Good Calories, Bad Calories.) It slows down digestion and leads us to feeling full sooner. More importantly, it doesn’t cause us to develop insulin resistance, a cause of diabetes, heart disease and an accelerator of fat deposition. I realize this is a lot to chew on. But skip the crackers and chew it over with some cheese.
