Some Recent Research

Truth to tell, I didn't have a brilliant idea for an article this week, so I thought it might be useful to look at some of the recent research on low carbohydrate dieting. As I said last week, I don't care if my Way of Eating is fashionable, but some of you are facing friends and family who are sure that your "fad" diet is terribly bad for your health. Some facts to counter their scare tactics surely wouldn't come amiss.

From Metabolism, the current issue:

The study started with the statement that low carbohydrate diets have a beneficial effect on weight, triglycerides, and HDL ("good" cholesterol,) but "may" cause undesirable changes in LDL ("bad" cholesterol) in some people. Right here we have the outright acceptance by medical researchers that a low carbohydrate diet works for weight loss, and has beneficial affects on two notable risk factors - that's something right there.

They continue by saying that they wanted to determine what effect of adding soluble fiber to such a diet would have on LDL levels. So they took 30 overweight and obese men, put them all on a low carbohydrate diet. They gave some soluble fiber capsules - 3 grams of fiber a day - , and others a placebo, in a double-blind trial.

The researchers kept track of whether the men were actually following their low carb program not only by dietary records, but also by testing for ketones. Compliance with the diet was "excellent."

Not surprisingly, both groups lost weight and body fat, and had their waists shrink. Both groups also lowered their blood pressure and blood sugar.

Both groups also had lower LDL. LDL dropped somewhat more rapidly in the fiber-takers, and also dropped a bit more. But the researchers concluded the difference was not big enough to be important - and also stated that the diet itself "led to clinically important positive alterations in cardiovascular disease risk factors."

From Hypertension, just last month:

A study of left ventricular hypertrophy, one of the most common forms of cardiomyopathy or "heart failure," discovered that a low carb/high fat diet actually improved the situation when the problem was caused by high blood pressure. The diet reduced the growth of the overgrown tissue, and improved the ability of the heart to contract. A low fat/high carb diet made matters worse. Keep in mind that this was in rats, but it's still an interesting bit of info.

Nutrition & Metabolism reported in their June issue that an obese diabetic patient who switched from the commonly recommended low fat, high carbohydrate diet to a low carbohydrate diet not only lost significant weight and improved glycemic control - big surprise! - but also reversed a six year decline in kidney function. It should be noted that one person does not a compelling study make. Still, since kidney damage is one of the boogeymen that is often used to scare low carbers, the story seemed worth telling.

In Osteoporosis International we find a 3 months study of 30 subjects regarding the effects of low carbohydrate diets on bone turnover. 15 of the subjects were instructed to eat Atkins-induction style - 20 grams of carb a day - for the first month, then 40 grams a day for the remaining 2 months. The other 15 subjects had no dietary restrictions. The researchers looked both at weight loss, and, more importantly, markers of bone loss. They found that the low carbers lost 6 times the weight of the no-diet group, which is no surprise. But they also found that there was no increase in markers of bone turnover in the low carb group, nor any significant change in bone turnover ratio. The threat of osteoporosis is another common cry of the anti-low carb set, so again, this is important information. (Osteoporosis - really crippling osteoporosis - runs in my family. I've seen it close up. I know how much pain it can cause, and I take it very seriously. So this is one of those issues I've been keeping an eye on.)

Nutrition & Metabolism, in its May 2006 issue, carried a study regarding the effect of a low carbohydrate diet on "emerging plasma markers" for cardiovascular disease - in other words, stuff that has only recently been recognized as a possible sign of heart disease. The researchers were already clear that low carb was beneficial for stuff like triglycerides and HDL, and for weight loss, so they wanted to know about the stuff that's less-discussed. They put 29 overweight men on a low carb diet for 12 weeks - 13% calories from carbohydrate, 60% from fat, 27% from protein. They also took a multivitamin every other day.

Average weight loss was 7.5 kilos (about 16 1/2 pounds.) The researchers felt this was because the subjects spontaneously ate about 30% fewer calories - the whole "just not as hungry" thing we're all familiar with. They ate less trans fats, which is unsurprising, since they're mostly found in carb-y foods like commercial fried foods and baked goods. Contrary to recent dire pronouncements from the CDC, their folate intake was unchanged.

How did various markers for coronary risk react? Homocysteine was unchanged. But C-reactive protein, which is a strong marker for inflammation, was reduced by 8%. Since research indicates that elevated C-reactive protein is a predictor not just for heart disease, but for diabetes and hypertension, this is very good news.

Another marker, TNF-alpha, was also reduced by just over 9%. (TNF stands for "tumor necrosis factor.") TNF-alpha is also a marker of inflammation, and can stimulate many of the ill effects of auto-immune diseases like rheumatoid arthritis, Crohn's Disease, psoriasis, and asthma. TNF-alpha also increases insulin resistance. Clearly, lower TNF-alpha is good news on a lot of fronts.

The article concluded that the diet led to weight loss, and that it not only improved the stuff doctors have been looking at for years, like HDL and triglycerides, but also the "emerging plasma markers."

This is nowhere near all the research that has come out in the past year; I'll cover more in the future. But be aware - the media may say that "low carb is dead," but as far as the research community is concerned, it is still very much alive - and more promising every day.