Diet-exercise combo helps elderly
Soy lowers breast cancer recurrence
Smoking and throat/stomach cancer
Exercise preserves heart muscle
Vitamin E lowers ALS risk
Vegetarian diet lowers cataract risk
Obesity is a dangerous condition that is increasing in the United States and around the world, largely due to health habits, not genetics. It is a particular problem for older adults because it exacerbates the decline in physical function and increases frailty associated with aging. A new study shows that a diet for weight loss combined with an exercise regimen works better than either program alone to improve physical function.
In a randomized, controlled trial, researchers evaluated 107 adults, with a Physical Performance Test (with higher scores indicating better physical status), and 93 of them completed the study. The participants were assigned to a control group, a diet group, an exercise group, or a combination of diet and exercise. The study went on for one year. (Villareal DT, et al., Weight loss, exercise, or both and physical function in obese older adults. N Engl J Med. 2011 Mar 31;364(13):1218-29.)
In addition to the Physical Performance Test, they also evaluated body composition, specific physical functions, frailty, bone density, and quality of life. The scores on the Physical Performance Test increased by 21 percent in the diet-exercise group compared with 12 percent in the diet group and 15 percent in the exercise group. All three treatment groups were better than the controls. Peak oxygen consumption increased by 17 percent in the diet-exercise group and only 10 and 8 percent, respectively, in the diet-alone and exercise-alone groups.
For weight loss, diet was better than exercise. Other measures were consistently better in the diet-exercise group. These included lean body mass and bone mineral density at the hip. Strength, stamina, balance, and gait all improved consistently and significantly in the diet-exercise group compared with the other groups.
A number of women who have had breast cancer are concerned with the potential risks of eating soy foods, such as tofu, tempeh, and soymilk. Some doctors have warned against it because of the mild plant-based estrogenic activity of some of the isoflavones contained in soy, but these concerns are misplaced. The research strongly suggests that natural soy foods are beneficial in breast cancer and other illnesses.
A news service recently reported on a presentation at the American Association for Cancer Research’s annual meeting concerning soy consumption after breast cancer (April 5, 2011 HealthDay News). The headline of the story indicated that “Soy foods OK after breast cancer” with a subtitle “Preliminary research finds no increased risk of recurrence.” This was misleading, because in actual fact, soy consumption was associated with a significantly reduced risk of breast cancer recurrence.
The researchers evaluated data from three studies on 9515 women for a follow-up period averaging 7.4 years. During that time, there were 1348 breast cancer recurrences and 1171 deaths (from breast cancer and other causes). Compared to women who ate the least soy, those in the upper 10 percent of soy intake had a 35 percent reduced risk of recurrence. They also had a 17 percent lower risk of death from all causes during the follow-up period.
Much evidence ties soy to lower risks of cancer, osteoporosis, heart mortality, and other illnesses. The antagonism to soy is often based on highly processed soy products, such as “texturized vegetable protein” or TVP. Also, much of the soy on the market is from genetically engineered beans (or genetically modified organisms-GMO). This latter problem is not an issue if you consume organic soybeans. Minimally processed organic soy, such as tofu, tempeh, and soymilk, or boiled fresh beans called edamame, provide benefits without the risks that some people have claimed.
Smoking tobacco has enough evidence for its associated health risks that it is hardly worth adding (and writing about) another one, but the latest research does just that. In a meta-analysis (study of studies) evaluating 33 published research papers, smoking was directly associated with esophageal and stomach cancers. (Tramacere I, et al., Tobacco smoking and esophageal and gastric cardia adenocarcinoma: a meta-analysis. Epidemiology. 2011 May;22(3):344-9.)
In this report, compared to never-smokers, those subjects who had ever smoked had a 75 percent increased relative risk of these cancers (the length of time since quitting was not documented, but the risks do go down with time). Current smokers had a 2.3 fold increased relative risk. The longer one goes without smoking, the lower many risks become, so it is never too early to quit (but unfortunately, sometimes it may be too late).
Muscle mass commonly decreases with aging, and this includes heart muscle, leading to functional decline. New research shows that this decline is not inevitable, at least not at the rates commonly seen in average, sedentary individuals. Researchers screened 148 subjects based on exercise history. Of these, 81 were sedentary subjects and 67 were lifelong exercisers recruited from the Aerobics Center Longitudinal Study, with documented exercise history for 25 years.
Using MRI testing with cardiac movies, they evaluated the mass of the heart muscle. What they found was that sedentary aging leads to a decline in the mass of the left ventricle but significant exercise can make a large difference. Sedentary young people had a ventricle mass index of about 55 (g/m2), while those over 50 who were sedentary had an index of about 48. Those over 65 who exercised 2 to 3 times per week had an index of about 53, just a bit less than sedentary young people. Those subjects over 65 who exercised 4 to 5 times per week had an index of about 63, greatly improved compared to sedentary people of any age. (Bella PS, et al., Lifelong exercise training demonstrates a dose dependent effect on…left ventricular mass… Presentation at Annual meeting of the American College of Cardiology, April 2, 2011.)
In the group who exercised 6 to 7 times per week, the index was far better than any other group studied, with an index of just under 70 g/m2 In addition to this improvement, the aerobic capacity, as measured by the oxygen uptake during exercise (peak VO2 ) was much superior in the group doing the most exercise. From sedentary youth numbers just over 30 ml/kg/min they found a decline to about 23 by 65 years old without exercise. Those getting the most exercise, on the other hand, increased their peak VO2 to over 40. They thus had more stamina and better overall physical function.
Along with vitamin C, vitamin E is one of the most commonly consumed dietary supplements. A number of studies have documented its benefits, especially for the heart (although some recent studies have called into question the conclusions from the earlier studies, I think these criticisms are unwarranted). Some of the other studies also show benefits from supplements of 1200 IU per day in slowing down the progression of Alzheimer’s disease and Parkinson’s disease. Now a new study shows that vitamin E can reduce the risk of developing amyotrophic lateral sclerosis (ALS, or Lou Gehrig’s disease).
Although ALS, a condition in which the nerve cells that control muscle activity progressively degenerate, is not common, it is an example of the protection afforded by this antioxidant vitamin. For this study, researchers combined the results of the Nurses’ Health Study, the Health Professionals Follow-up Study, the Cancer Prevention Study II Nutrition Cohort, the Multiethnic Cohort Study, and the NIH-AARP Diet and Health Study (pooling data from so many large studies allowed them to accumulate enough data for such a rare disorder).
Over the entire group they did not see an association with vitamin E, but what they found was that ALS rates declined with increasing years of use. For non-users and those who had been taking vitamin E for less than one year, the rates of ALS were similar. For those taking vitamin E for 2-4 years, the rate of ALS was 23 percent lower than among non-users. Among those taking vitamin E for 5 years or more, the rate of ALS was 36 percent lower than for non-users. (Wang H, et al., Vitamin E intake and risk of amyotrophic lateral sclerosis: a pooled analysis of data from 5 prospective cohort studies. Am J Epidemiol. 2011 Mar 15;173(6):595-602.)
Those subjects with the highest intake of vitamin E had a 21 percent reduction in relative risk of ALS compared to those with the lowest intake. This and earlier studies suggest neurological benefits from vitamin E.
Age related cataracts are a significant cause of functional decline (even though they can be treated surgically with excellent results). A new study from Oxford, England evaluated the relationship of diet to cataract risk. (Appleby PN, et al., Diet, vege-tarianism, and cataract risk. Am J Clin Nutr. 2011 May;93(5):1128-35.)
In their evaluation of 27,670 non-diabetic subjects over 40 years old, the researchers found that diet was indeed related to cataract. Those with the highest meat consumption had the greatest risk of developing cataracts. Those with moderate meat consumption had almost the same risk. Those who ate very little meat had a 15 percent reduction in cataract risk, and those who ate only fish plus vegetarian foods had a 21 percent lower risk. Finally, for vegetarians and vegans the risks were 30 and 40 percent lower, respectively. Vegetarian and vegan diets, with healthful selections of whole, minimally-processed foods, are valuable for heart protection, cancer prevention, and many other health benefits. Cataract prevention is just one of them.
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