November Health Pearls on Nuts, Knees and Vitamin D

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November 29, 2013

#1 We have already seen that a Mediterranean style diet, rich in nuts, is healthy. This month, researchers from Harvard reviewed nut consumption in over 110,000 health professionals from 1980 through 2010. Eating any nuts reduced the risk of dying by 7%. The more they ate, the better, so those with daily nut consumption reduced their risk of dying by 20%. Specifically, they were less likely to die from cancer, heart disease or respiratory disease.

Other studies have shown that nuts are associated with a decreased risk of adult onset diabetes, colon cancer, high blood pressure and inflammatory diseases. It is not clear which of the many good nutritional qualities (such as unsaturated fats, fiber, minerals , vitamins and anti-oxidants, to name a few) account for the benefits observed. The findings held true for peanuts, which are actually legumes, as well as other nuts. Despite the high caloric content, increased nut consumption was associated with less weight gain and lower waist circumference. Obviously, it matters what else you eat in addition to the nuts. Perhaps people who ate nuts also ate more vegetables and less high calorie foods in general.

This one study demonstrates association, not cause and effect, between nut consumption and decreased death rate, but in conjunction with other data, the idea that nut consumption is responsible for decreased mortality is very plausible. Part of the benefit of Mediterranean diets is likely the inclusion of nuts.
SOURCE: NEJM 2013; 369:2001-11.

#2 You might not consider that osteoarthritis could shorten your life. To the extent that it decreases your physical activity and increases your intake of anti-inflammatory medications, it could, probably by increasing your risk for cardiovascular disease.

Researchers reporting in the British Medical Journal looked at two groups of 153 patients. All subjects had moderate to severe osteoarthritis; one group had total hip or knee replacements, the other group did not have surgery. Those who had surgery had a 12% reduction in risk of cardiovascular disease compared with those who didn’t have surgery. The patients with surgery benefited whether or not they had risk factors for heart disease.

Of course, surgery is associated with some risk, but when moderate or severe osteoarthritis interferes with everyday activities and exercise, it may be time to discuss the risks and benefits of surgery with your physician.
SOURCE: Ravi et al., BMJ 2013; 347:16187

#3 Vitamin D levels aren’t always what they seem to be. We routinely tell people to limit their sun exposure but we need the sun to help our bodies produce the active form of Vitamin D. When the level is low, bone formation is affected, leading to osteopenia and osteoporosis.

It has been noted that black Americans have lower levels of vitamin D in their blood, but higher bone densities than white Americans, which didn’t seem to make sense. A study published this week in the New England Journal of Medicine explains that this might be due to black Americans genetically having a lower level of the protein that binds vitamin D. This means that for a given total level of vitamin D, less is bound to protein, so there is more floating free and available to help form stronger bones. In the future, we may need to measure ‘free vitamin D’ to know who really needs to take a vitamin D supplement.  For now, the recommendation is for 800 International Units (IU) daily of Vitamin D3 – it should be the D3 form for optimal absorption.  I have some of my patients on several thousand units a day for months, if needed, to keep the level at 30.  Fortunately, the side effects associated with excess calcium intake, like kidney stones and unwanted calcification in the coronary arteries, do not pertain to excess Vitamin D.
SOURCE: NEJM 2013; 369:1991-2000.