Does glycemic index affect heart risks?
Is exercise valuable for health?
CoQ10 and statin-related muscle pain
Whole grains lower mortality risk
Vitamin E and blood pressure
Glycemic index is a measure of the effect that a food has on blood sugar (glucose) just after eating. A diet of high-glycemic-index foods has been thought to raise risk factors for heart disease, such as LDL cholesterol, triglycerides, and total cholesterol. A new study suggests that this may not be the case. Researchers examined 163 overweight adults with normal to moderately high blood pressure, and put them on 4 different diets that contained all of their meals, snacks, and calorie-containing beverages. Each participant was given each of the four diets for five weeks, with a break between each diet. This was a controlled feeding study, not dependent on questionnaires or memory.
All of the diets were based on a healthful DASH-type (Dietary Approach to Stop Hypertension) diet as a foundation and then varied to be high-carb, high glycemic index; high-carb, low-glycemic index; low-carb, high-glycemic index; or low-carb, low-glycemic index. The outcomes they looked at were insulin sensitivity, levels of LDL cholesterol, HDL cholesterol, triglycerides, and systolic blood pressure. (Sacks FM, et al., Effects of high vs low glycemic index of dietary carbohydrate on cardiovascular disease risk factors and insulin sensitivity: the OmniCarb randomized clinical trial. JAMA. 2014 Dec 17;312(23):2531-41. doi: 10.1001/jama.2014.16658.)
With high dietary carb intake, a low glycemic index actually reduced insulin sensitivity, increased LDL levels, and did not affect the other measures. With a low-carb diet, compared to the high-glycemic-index foods, the low-glycemic-index foods did not affect outcomes, other than a small, but significant, change in triglycerides from 91 to 86 mg/dL. In the primary diet contrast (low-carb, low glycemic versus high-carb, high-glycemic), the diets did not affect systolic blood pressure, HDL- or LDL-cholesterol, or insulin sensitivity, but there was a significant decrease in triglycerides from 111 to 86 mg/dL.
The authors concluded that in the overall scheme of things, and with a basically healthy diet (high in vegetables, legumes, whole grains, and fruits, low in salt, and with reduced amounts of animal products) the glycemic index was not a useful guide to dietary choices.
When Dr. Denis Burkitt studied the native African diet in the 1950s, their dietary staples were potatoes, bananas, corn meal, and beans. They were virtually free of heart disease, hypertension, strokes, diabetes, colon cancer, appendicitis, and diverticulitis. He attributed this to the high fiber content of their diet (about 100 grams per day). In the United States, fiber intake in adults in 1987 was about 11 grams per day, and that rose to 16 grams by 2001, and continued to increase slightly by 2010. In 2012, only 3 percent of Americans met the recommended fiber intake, and that is already alarmingly low at only 14 grams per day (although newer guidelines have raised it to 37 grams per day for 20 to 50 year olds).
Choosing a diet high in fiber is more important than worrying about glycemic index, and fiber is found in fruits, vegetables, whole grains, beans, seeds, and nuts. This dietary selection is great for weight control, but for those few who need to add weight you can choose more avocados, sesame tahini, peanut butter, and nuts. Animal products (flesh foods, dairy, and eggs) are devoid of fiber.
A neighbor on the machines at the gym was exercising reluctantly as she has an aversion to exercise, even though she thinks it must be good for her. She recently noted that a news article reported on a study that showed “exercise does not help you live longer” because, according to the article “those who exercised four hours a week had the same mortality as those who did not exercise.” This did not ring true to me, so I looked up the news reports and the article, and those conclusions (and possibly revised public attitudes) were not justified.
In the news article, they did report that exercising up to 2.4 hours a week in 3 sessions did confer life-extension benefits. For joggers, they found that 12 minute miles was the best pace (that’s 5 miles per hour). HOWEVER, further along in the news article, they pointed out that the pace was estimated by the researchers based on self-reporting by the subjects as to whether their exercise was “slow, average, or fast,” and the age range of the subjects ranged from 20 to 95 years. (HealthDay News, Feb 2, 2015).
The research was part of the Copenhagen City Heart Study examining 1098 healthy joggers and 3950 healthy non-joggers followed for 12 years. (Schnohr P, et al., Dose of jogging and long-term mortality: the Copenhagen City Heart Study. J Am Coll Cardiol. 2015 Feb 10;65(5):411-9. doi: 10.1016/j.jacc.2014.11.023. Compared to sedentary non-joggers, those who exercised 1 to 2.4 hours per week had the lowest mortality, a 71 percent reduction in the likelihood of dying during the study. They also found that self-reported “strenuous” joggers had about the same mortality as those who did not exercise (this is contrary to findings in some other studies).
A number of critiques of this study appeared, including one in an editorial in the same journal, and a number in the New York Times article itself and in the comments section of that report (NYT, Feb 4, 2015). One problem was that the pool of vigorous joggers consisted of only 80 subjects. In the editorial accompanying the journal article, Dr. DC Lee noted many flaws aside from the small pool of vigorous joggers. He did point out, however, that the article might motivate some people to exercise even the small amount that would provide them many health benefits compared to being completely sedentary.
Dr. Lee also published another complete article last August showing that exercise lowered mortality from all causes and from cardiovascular disease. These researchers evaluated 55,137 adults from 18 to 100 years old, including over 13,000 runners, and followed them for 15 years. Compared with non-runners, runners had 30 percent lower all-cause mortality, and 45 percent lower cardiovascular mortality. They noted that more running provided benefits with a dose-response relationship, meaning more exercise provided greater benefits. (Lee DC, et al., Leisure-time running reduces all-cause and cardiovascular mortality risk. J Am Coll Cardiol. 2014 Aug 5;64(5):472-81.)
People who hate exercise will jump on the headlines from this report and conclude that they do not need to exercise. This is not a justifiable conclusion, but as my colleague John McDougall says, “people love to hear good things about their bad habits.” It is still true that regular exercise that includes some resistance training and some aerobics is good for its many health benefits and a decreased risk of premature death. In general, the more the better. While the news article did report on the study’s flaws, you had to read far into the article to find out that almost any level of exercise is good for you.
Coenzyme Q10 (CoQ) may reduce the side effects of statin drugs, particularly one of the most common negative effects: myopathy, or muscle pain. Statins lower the serum level of CoQ, and many studies have shown that CoQ supplements help to restore it. In a controlled study, researchers recruited 50 patients who reported muscle pain from statin treatment. They treated half of them with 50 mg of CoQ twice per day for 30 days, while the other half were given a placebo.
At the start of the study, patients filled out a Brief Pain Inventory (BPI) questionnaire and had blood tests. Both were repeated at the end of the study. After 30 days, the Pain Severity Score (PSS) was reduced from 3.9 to 2.9 in the CoQ group, and the Pain Interference Score (PIS) was reduced from 4.0 to 2.6 in that group. The PSS and PIS did not change in the control group. Overall, the CoQ supplements reduced the statin-related muscle symptoms in 75 percent of the patients. (Skarlovnik A, et al., Coenzyme Q10 supplementation decreases statin-related mild-to-moderate muscle symptoms: a randomized clinical study. Med Sci Monit 2014; 20:2183-2188.)
A meta-analysis published in January evaluated the benefits from CoQ supplements in statin-induced myopathy symptoms. They evaluated five studies with a combined total of 253 participants. In 2 of the 5 studies, CoQ had a statistically significant effect on muscle pain, and every study showed some pain reduction (if it were a random effect, you would expect some studies to show more pain and some less or no change). Overall, the doses of CoQ ranged from 50 to 300 mg. The authors reported “a trend” toward a decrease in muscle pain (it actually declined by 53 percent), but this was not “statistically significant.” For those patients whose pain decreased, I am sure that was significant to them. (Banach M, et al., Effects of coenzyme Q10 on statin-induced myopathy: a meta-analysis of randomized controlled trials. Mayo Clin Proc. 2015 Jan;90(1):24-34.)
For patients on statins it seems prudent to try CoQ for treatment. Coenzyme Q10 has no side effects up to very high doses. It is effective treatment for congestive heart failure and hypertension and has benefits for neurological disorders such as Alzheimer’s and Parkinson’s disease, with studies showing safety up to at least 2400 mg per day. I recommend ubiquinol as the preferred form, usually in doses of 100 to 200 mg, once or twice per day, and higher doses for the neurological disorders. With no risk and evidence of benefit, I see no reason not to try it, and I often wonder why doctors are reluctant to suggest it, when many of the treatments they administer are more risky but have no better evidence of benefit.
Whole grains are once again in the medical news. They have been associated with a lower risk of major chronic diseases, such as diabetes and heart disease. In a new report of a prospective study, researchers investigated 74,341 women from the Nurses’ Health Study and 43,744 men from the Health Professionals Follow-Up Study all of whom were free of cardiovascular disease (CVD) and cancer at the start of the study. These studies ran for 24 to 26 years. Whole grain consumption was evaluated using validated questionnaires and updated every 2 or 4 years.
Over the years of the study, they documented 26,920 deaths. After adjusting for a number of confounding variables, including age, smoking, body mass index, physical activity, and Healthy Eating Index score, they found that whole grain consumption was associated with a lower total and CVD mortality, but not cancer mortality (although other studies have shown benefits for cancer prevention). (Wu H, et al., Association between dietary whole grain intake and risk of mortality: two large prospective studies in US men and women. JAMA Intern Med. 2015 Jan 5. doi: 10.1001/jamainternmed. 2014.6283. [Epub ahead of print])
Overall, they found a 9 percent reduction in all-cause mortality for those in the highest quintile of whole grain intake compared to those in the lowest quintile. Those in the highest quintile of whole grain intake had a 15 percent reduction in CVD mortality. The investigators estimated that for every serving of whole grains (28 grams or 1 ounce) per day total mortality was lowered by 5 percent, and CVD mortality by 9 percent.
I think by now everyone recognizes the dangers of refined carbohydrates (white flour and sugar, in particular). Unfortunately, many people think of all grains as “carbs” and fail to make the distinction between whole grains and refined grains (whole wheat versus white flour; brown rice versus white rice). Many of my colleagues also write newsletters and books ignoring the difference, and they ignore literature such as this that shows the great advantage of whole grains for health.
Whole grains contain fiber, phytochemicals, and essential fatty acids, all of which could contribute to their health benefits. I recommend regular consumption of whole wheat, rye, and barley (unless you have celiac disease or are otherwise are sensitive to gluten), and non-gluten grains, such as oats, brown rice, whole corn, millet, buckwheat, and quinoa. Always avoid refined grains.
Vitamin E is an excellent biological antioxidant that has many beneficial health effects. One is helping to control blood pressure. In a Japanese study, researchers evaluated data from the National Health and Nutrition Survey (NHNS) done in 2007, including data from 1405 males and 2102 females with average ages of 63.5 and 62.4, respectively. They grouped the subjects into thirds of low, middle, and high vitamin E intake.
Those groups with higher vitamin E intake had a lower percentage of subjects with hypertension. Those in the middle and upper thirds had 27 percent and 19 percent lower odds of having hypertension. (Kuwabara A, et al., The association between vitamin E intake and hypertension: results from the re-analysis of the National Health and Nutrition Survey. J Nutr Sci Vitaminol (Tokyo). 2014;60(4):239-45.)
Not all studies confirm this result, but some do. In 2002, researchers studied 70 mildly hypertensive subjects in a blinded, placebo-controlled trial. They gave them 200 IU per day of vitamin E or a placebo for 27 weeks. They measured blood levels of vitamin E at the beginning and end of the study. At the end of the study, those subjects on the vitamin E had a 24 percent drop in systolic blood pressure and a 12.5 percent drop in diastolic blood pressure. The placebo group had virtually no change in these measures. The researchers speculated that vitamin E protected the endothelium and led to more production of nitric oxide, a blood vessel relaxant. (Boshtam M, et al., Vitamin E can reduce blood pressure in mild hypertensives. Int J Vitam Nutr Res. 2002 Oct;72(5):309-14.)
Natural vitamin E (d-alpha tocopherol, rather than synthetic “dl-alpha”) may help patients control blood pressure. I recommend 200 to 400 IU per day, or more for people with neurological diseases. It is also important to include gamma tocopherol in substantial amounts to maintain the natural balance of the different forms of vitamin E.