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March 2012

Citrus lowers women’s stroke risk
Omega-3 oils protect brain
Green tea helps the elderly
Obesity increases asthma in children
Sugar drinks increase heart disease
Dietary cadmium raises breast cancer

Citrus lowers women’s stroke risk

New research shows that eating citrus fruits helps to reduce the risk of strokes in women (there is no reason to suspect that the same benefits would not accrue to men also). Researchers did a prospective study on 69,622 women as part of the Nurses’ Health Study. They calculated the total flavonoid intake and subclasses of flavonoids, including flavanones. (Cassidy A, et al., Dietary Flavonoids and Risk of Stroke in Women. Stroke. 2012 Feb 23. [Epub ahead of print])

They evaluated the subjects with food-frequency questionnaires every four years and followed them for a total of 14 years. By the end of the study period, they confirmed 1803 incident strokes. Women with the highest flavanone intake had a nearly 20 percent lower risk of ischemic stroke (due to obstructed blood flow rather than hemorrhage) compared with those women who had the lowest flavanone intake.

The main sources of flavanones in this group were citrus fruits and juices. Total flavonoid intake was not associated with the favorable stroke risk reduction, just the flavanone subclass.

Other studies have shown that flavonols, flavanones, and flavones (all subclasses of flavonoids) are associated with cardioprotective effects and anti-carcinogenic properties. Flavanones are the major flavonoid group in citrus fruits, including oranges, grapefruit, tangerines, lemons, and limes. Flavanone content is higher for the whole fruit than for the juices. Other flavonoids are available in a wide variety of fruits, vegetables, whole grains, and legumes, as well as tea, chocolate and wine. (While wine might decrease stroke risk, it might also increase the risk of breast cancer.)

Omega-3 oils protect brain

Some mental decline with age is inevitable, but the typical accelerated decline that we commonly see is not simply a consequence of aging, but of lifestyle choices. It is influenced by exercise, stress, attitude, and also by dietary choices. A new study of 1575 subjects, including 854 women, shows that maintaining mental function is to some extent related to the level of essential fatty acids in the red blood cells (RBC). The subjects’ ages ranged from 58 to 76 years and they were evaluated for performance on cognitive tests and brain volume based on an MRI.

Subjects with the lowest levels of DHA (docosahexaneoic acid, an omega-3 fatty acid) in the RBC had a lower total brain volume than those with the highest levels of DHA. Participants with the lowest DHA and the lowest omega-3 index (RBC DHA + EPA, or eicosapentaenoic acid) also had lower scores on tests of visual memory, executive function, and abstract thinking than those with the highest levels. (Tan ZS, et al., Red blood cell omega-3 fatty acid levels and markers of accelerated brain aging. Neurology. 2012 Feb 28;78(9):658-64.)

These results were seen in subjects who did not have clinical evidence of dementia, but the concern is the long-term consequences of the metabolic pattern associated with dementia. DHA and EPA (the omega-3 oils found in fish such as salmon) are not exactly essential fatty acids because your body can make them from alpha-linolenic acid (ALA, found primarily in flaxseeds, walnuts, pumpkin seeds, sesame seeds, and chia seeds, and in smaller amounts in canola and soybeans). Some people do not convert ALA efficiently into the EPA and DHA and may do better with these in the diet (or taken as dietary supplements from fish oil).

Green tea helps the elderly

Lifestyle choices not only influence the risk of cognitive decline with age, they also affect physical abilities. A new study shows that elderly subjects who regularly drink green tea maintain better agility and independence as they age. (Tomata Y, et al., Green tea consumption and the risk of incident functional disability in elderly Japanese: the Ohsaki Cohort 2006 Study. Am J Clin Nutr. 2012 Mar;95(3):732-9.) Green tea does have some caffeine content, so if you are sensitive to small amounts of caffeine you can try decaffeinated green tea or take extracts as supplements.

This Japanese prospective study evaluated 13,988 individuals over 65 years old. They gathered data on their green tea consumption and other lifestyle factors by means of a questionnaire in 2006 and followed them for three years. Compared to those who consumed less than 1 cup of green tea daily, those who consumed 1-2 cups had a 10 percent lower incidence of functional disability, for 3-4 cups the loss of function was 25 percent lower, and for more than 5 cups the it was 33 percent lower.

The green tea drinkers also had other lifestyle factors that were helpful, but the researchers accounted for these before drawing their conclusions. These included better education, less smoking, and more fish, fruits, and vegetables in their diets. Other studies have shown that green tea is associated with lower risk of stroke, cognitive impairment, and osteoporosis.

Obesity increases asthma in children

Obesity creates a number of health problems for children and adults. A recent study shows that children and teens who are overweight are more likely to suffer from asthma than those who are normal weight, as measured by body mass index (BMI). The data were derived from medical records of 681,122 patients aged 6-19 years with measured height, weight, and asthma diagnoses. (Black MH, et al., Higher prevalence of obesity among children with asthma. Obesity (Silver Spring). 2012 Jan 17. doi: 10.1038/oby.2012.5. [Epub ahead of print])

Among the subjects, 18.4 percent had a history of asthma and 10.9 percent had current asthma. Compared to those with normal BMI, those who were simply overweight had a 22 percent higher chance of having asthma, those who were moderately obese had a 37 percent higher incidence, and those who were extremely obese had a 68 percent higher incidence of asthma. Interestingly, there were unexplained racial/ethnic differences among the subjects’ asthma-obesity relationship.

Overall, black youth are nearly twice as likely to have current asthma and Hispanic youth are 25 percent less likely than non-Hispanic white youth. However, the influence of obesity on asthma was strongest in Hispanic youth and weakest in black youth. Among youth with asthma, increasing BMI was associated with more frequent ambulatory and emergency department visits, as well as increased use of inhaled and oral corticosteroids.

Sugar drinks increase heart disease

Refined sugar is prevalent in the diets in developed countries, and its use is spreading around the world. It is undoubtedly a contributor to obesity and diabetes in the long term, and often acute symptoms associated with hypoglycemia and Candidiasis. A new study shows that it is also almost certainly a contributor to the development of heart disease. As heart disease is the number one killer in the United States (as well as other developed countries, including France, in spite of the so-called French paradox), it is important to understand the role of sugar in the risk of heart disease.

This research from the Harvard School of Public Health was part of the Health Professionals Follow-up study, and it included 42,883 men. They were followed for 22 years and evaluated for their consumption of sugar-sweetened beverages, mainly sodas, as well as the consumption of artificially sweetened (diet) sodas. (de Koning L, et al., Sweetened beverage consumption, incident coronary heart disease and biomarkers of risk in men. Circulation. 2012 Mar 12. [Epub ahead of print].) They examined the relationship of these beverages to fatal and non-fatal heart attacks (coronary heart disease or CHD).

During the study they found 3683 CHD cases. Participants in the top quartile of sugar-sweetened beverage intake had a 20 percent higher risk of CHD than those with the lowest intake. The intake of diet sodas was not related to CHD, indicating that sugar was the culprit. Of course, diet drinks also have detrimental ingredients, including the artificial sweeteners, but other than those, the ingredients are pretty much the same as regular sodas.

The researchers also evaluated blood lipids (HDL, Lp(a), and triglycerides) and serum markers of inflammation, including CRP, interleukins, and tumor necrosis factors). The high sugar-sweetened-beverage consumers had significant adverse changes in all of these markers. The recommendation of the American Heart Association is that people should consume fewer than three sugary sodas per week, but I wonder why it would not be better to avoid them altogether. Better choices would be water, sparkling water, or either of those with a splash of natural, unsweetened fruit juice (just enough to color the water).

Dietary cadmium raises breast cancer

A new study from Sweden shows that exposure to dietary cadmium, a toxic metal that mimics the effects of estrogen, increases the risk of breast cancer in women who are not obese. Cadmium is found in many farm phosphate fertilizers, so, other than smoking, food is the most common source of human exposure. Although absorption is low, it accumulates in the body over time, as relatively little cadmium is excreted. It is a known carcinogen, related to cancers of the lung, endometrium, bladder, and breast.

In this current research on 55,987 postmenopausal women, they were followed for an average of over 12 years. Dietary cadmium intake was positively associated with the incidence of breast cancer. Those with the highest exposure had a 21 percent increased risk compared to those with the lowest intake. For lean and normal-weight women, the increased risk was 27 percent for estrogen receptor positive tumors (the risk was also increased for estrogen-receptor-negative tumors, but it was not statistically significant).

The primary sources of cadmium in the diets of these women were whole grains and vegetables, which makes it important to choose organic foods as much as possible. These foods also contain anti-carcinogenic compounds, but apparently not enough to make up for all of the effects of cadmium. (Julin B, et al., Dietary cadmium exposure and risk of postmenopausal breast cancer: a population-based prospective cohort study. Cancer Res. 2012 Mar 15;72(6):1459-66.) Cadmium can be removed from the body with chelation therapy (intravenous or oral).

The effect of cadmium was not as evident in overweight and obese women. Fatty tissue produces estrogens, and this probably overrides some of the estrogenic effects of cadmium. The ideal strategy for breast cancer prevention is to eat organic foods, especially whole grains, fruits, vegetables, and legumes, and to maintain a normal weight through diet and exercise.

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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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