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June 2012

Topics:

Blueberries, apples, and pears lower diabetes
Fish may lower risk of colon cancer
Exercise and breast cancer risk
Low-carb diet increases heart risk
Build muscle with lighter weights

Blueberries, apples lower diabetes

Blueberries, apples and pears are rich in flavonoids (such as flavonols, flavones, and anthocyanins), as well as fiber (such as pectin) and minerals. While they contain naturally occurring fruit sugar, they appear to be associated with a lower risk of diabetes. Consuming these fruits improves insulin sensitivity, helping to keep blood sugar levels in control. On the other hand, insulin resistance is associated with the development of diabetes as well as cardiovascular disease.

Researchers followed up a total of 70,359 women in the Nurses’ Health Study (NHS), 89,201 women in the NHS II, and 41,334 men in the Health Professionals Follow-up Study. All of the subjects were free of diabetes, cardiovascular disease, and cancer at the start of the study. With such a large study population, they had 3,645,585 person-years of follow-up, during which time they documented 12,611 cases of type 2 diabetes. (Wedick NM, et al., Dietary flavonoid intakes and risk of type 2 diabetes in US men and women. Am J Clin Nutr. 2012 Apr;95(4):925-33.)

Those subjects with the highest intake of anthocyanins (two or more servings of blueberries per week) had a 23 percent lower risk of diabetes compared to those who consumed less than one serving per month. The risk reduction was the same for those who consumed five or more servings of apples/pears per week compared to those who ate less than one serving per month.

Other studies have shown an association of these flavonoids with a lower risk of both high blood pressure and death from cardiovascular disease. Flavonoids are also present in vegetables, whole grains, and beans, but these fruits are especially rich in them. A serving of blueberries is half a cup. Consuming the juices of these fruits instead of the whole fruit means missing out on the benefits of the pectin and other fibers. Juices have more concentrated sugars, and are associated with an increased risk of diabetes. If you would like a fruit drink, add 10 to 25 percent juice to water or sparkling water, or use a VitaMix or other blender to make whole fruit smoothies.

Fish may lower risk of colon cancer

Fish consumption may be related to a lower risk of heart disease, possibly because of the omega-3 oils contained in many fish (such as salmon and sardines), and possibly for other reasons. A new review of studies shows that eating fish may also reduce the risk of colon and rectal cancers. The researchers evaluated 41 studies over a 20-year period, including 22 prospective cohort studies and 19 case-control studies. (Wu S, et al., Fish consumption and colorectal cancer risk in humans: a systematic review and meta-analysis. Am J Med. 2012 Jun;125(6):551-559.e5.)

Those subjects eating the most fish had a 12 percent reduction in colorectal cancers compared to those who ate the least fish. However, the reasons for the difference are not clear as they did not account for the kinds of fish being eaten (high or low in omega-3 oils) nor the method of preparation. It also did not evaluate whether the fish eaters had other healthful lifestyles. Grilling (whether fish or other foods) might increase the risk of cancer while steaming or poaching might decrease it. The benefit might be from substituting fish for processed meats. It might also be from eating less processed foods such as white flour and sugar.

Exercise and breast cancer risk

Exercise is more important than ever with our typically sedentary lifestyles. I am very active with brisk walking, lifting weights, “excessive” gardening and mowing, and other activities. However, in spite of that, and in addition to driving, I still spend much of my time at my desk doing research and writing my newsletter, answering emails, and exploring information on the web. Overall, compared to primitive peoples, I am relatively sedentary. It is known that physical activity reduces breast cancer risk, but how much risk reduction and how much exercise were not clear in earlier studies.

In a new report, researchers evaluated 1504 cases of breast cancer with 1555 controls from the Long Island Breast Cancer Study Project. Those women in the upper third of activity level had a 30 to 33 percent reduction of breast cancer risk. Premenopausal women had a slightly greater benefit than postmenopausal women. The exercise that these researchers referred to was what they called “recreational physical activity,” which did not have to be intense.

During reproductive years, the benefit was seen with 10 to 19 hours of activity, and in postmenopausal women with an average of 9 to 17 hours per week. They also noted that women who were overweight or obese or who gained weight during the study period were at an increased risk of breast cancer. They did not benefit as much from exercise as their normal-weight peers, but there was still some risk reduction.

Low-carb diet increases heart risk

Weight-loss diets are notoriously unsuccessful in the long term. People generally lose weight on any of them with relatively minor differences from one plan to another, but after a year or two, 98 percent of them gain back most of the weight or even more than they lost. The only approach that might work is to establish a healthy, whole-foods eating plan (no refined carbs like sugar and white flour) that you can stay on for the rest of your life and combine that with regular exercise. While this may be difficult for obese people to do (partly because they do not lose a lot of weight right away and get discouraged) it is the only approach that is likely to lead to better health as well as long-term weight control.

High protein, low carbohydrate diets have been around for decades, but for long-term health they create problems and documentation of any benefit is weak, other than for short-term weight loss. A new study of the low-carb, high-protein diet shows that it is associated with an increased risk of heart disease. Researchers evaluated 43,396 Swedish women, aged 30 to 49 years at the start of the study and followed them for an average of 15.7 years. (Lagiou P, et al., Low carbohydrate-high protein diet and incidence of cardiovascular diseases in Swedish women: prospective cohort study. BMJ. 2012 Jun 26;344:e4026. doi: 10.1136/bmj.e4026.)

They used an extensive dietary questionnaire to create a low-carb, high-protein score ranging from 2 to 20, with those scoring 20 being most closely adherent to the diet. While there are a number of variations of this diet, it is commonly associated with the Atkins’ diet developed by Robert Atkins, MD. He published many books on his approach and has many devoted followers.

In this study, adherence to the diet was associated with an increased incidence of cardiovascular disease. Every 10 percent decrease in carbohydrate or increase in protein, or every 2-point increase in the score raised the cardiovascular incidence by four to five percent. The disease outcomes they studied included heart disease, stroke, peripheral arterial disease, and subarachnoid hemorrhage, and those risks were all similarly associated with the diet.

The lead author of this study was quoted in HealthDay News (June 26, 2012) saying “Although [the diets] may be nutritionally acceptable if the protein is mainly of plant origin, such as nuts, and the reduction of carbohydrates applies mainly to simple and refined [carbohydrates] like unhealthy sweeteners, drinks and snacks, the general public does not always recognize and act on this guidance.” Overall, those women who followed the high-protein low-carb diet most closely had a 28 percent increased risk of vascular diseases compared to those who chose foods at the other end of the dietary scale.

It is not as though you cannot eat a lot of vegetables on a high-protein diet, but the caloric intake of the protein sources (meat, chicken, and cheese, for examples) is so high that there is not enough room in the diet for the foods high in protective phytochemicals, such as vegetables, fruits, whole grains, beans, seeds, and nuts. The animal foods that usually make up these diets are devoid of fiber, which is such an important component of the diet.

Build muscle with lighter weights

Strength training (also called resistance exercise) in addition to aerobic exercise has its own benefits in helping to build muscle mass, control blood sugar, reduce cardiovascular risks, build bone density, improve immune function, and decrease the likelihood of injury. It also improves physical capacity (lifting heavier bags from the grocery store), gait and coordination, and performance of normal activities of daily living. You may see people straining to lift the heaviest weight possible in order to build these muscles, but it is not necessary to work at the highest resistance levels to achieve benefits.

The usual recommendations have been that lifting weight at 70 to 80 percent of maximal strength for 8 to 12 repetitions is required to maximize muscle growth. However, researchers at McMaster University in Canada have found that subjects can achieve muscle protein synthesis (MPS) with lighter weights and an increased number of repetitions. (Burd NA, Bigger weights may not beget bigger muscles: evidence from acute muscle protein synthetic responses after resistance exercise. Appl Physiol Nutr Metab. 2012 Jun;37(3):551-4.)

Using just 30 percent of maximal intensity resistance, but increasing the number of repetitions to achieve muscle fatigue results in MPS the same way as using higher weights with fewer repetitions. While this does take longer, there is less risk of injury and less likelihood of abandoning the exercises because they seem too difficult.

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CONSULTATIONS:

From September to June, I see patients in New Smyrna Beach, Florida.
Call 386-409-7747, or send an email to to make arrangements.

In summer, I have a variable schedule, and I see patients in offices at the
Rothfeld Center for Integrative Medicine in Waltham, Massachusetts. For appointments, send an email to make arrangements, or call: 386-409-7747.

I primarily do phone consultations, as well as email and instant messaging consults.


Information herein is not medical advice or direction. All material in this newsletter is provided for information only. Its contents should not be used to provide medical advice on individual problems. Consult a health care professional for medical or health advice.

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