Soy helps hot flashes
Tooth scaling lowers heart risk
Zinc shortens colds
Coffee lowers mortality
Soybeans contain a number of beneficial phytochemical compounds (as well as being a source of protein, vitamins, and minerals). A recent review of studies on soy isoflavones and menopausal symptoms analyzed the efficacy of these compounds in relieving hot flashes. Some studies have found no such benefits, while others have found significant benefits from both soy foods and supplements.
For this systematic review, researchers examined 19 trials until the end of 2010. They looked at the effect of extracted or synthesized isoflavones on the frequency, severity, or a composite score for hot flashes compared with the effects of placebo. They selected 17 of the trials for the analysis. (Taku K, et al., Extracted or synthesized soybean isoflavones reduce menopausal hot flash frequency and severity: systematic review and meta-analysis of randomized controlled trials. Menopause. 2012 Mar 19. [Epub ahead of print].)
They found that ingestion of an average of 54 mg of soy isoflavones for 6 weeks to 12 months significantly reduced the frequency of hot flashes by 20.6 percent compared with placebo. They also found a reduction of severity of the hot flashes by 26.2 percent. Those isoflavones supplements that contained at least 18.8 mg of genistein (just one of the isoflavones contained in soy) were more than twice as effective in reducing hot flash frequency as those with lower levels of genistein.
For those women who do not tolerate hormone replacement therapy or wish to avoid it for various reasons, soy consumption and/or isoflavone supplements might provide them many of the benefits. If they do choose to use hormone replacement, I strongly recommend the bio-identical forms of the hormones in the appropriate balance for their needs.
Poor oral hygiene has long been considered a risk factor for cardiovascular disease. The assumption has been that chronic inflammation from gum disease or the bacteria residing in the region between the gums and the teeth below the gum line were related to the development of atherosclerosis. It is not clear that these are the causal mechanisms, but they do seem plausible (more on this later).
A current study shows that professional tooth cleaning with scaling of the teeth below the gum line does reduce cardiovascular disease.
This was a prospective population-based study. Using information on a random sample of one million persons in the Taiwan National Health Insurance Research Database, researchers looked for all those subjects over 50 years old who had received at least one scaling of teeth in the year 2000. (Chen Z-Y, et al., The association of tooth scaling and decreased cardiovascular disease: a nationwide population-based study. Am J Med June 2012;125(6), 568-575.)
Subjects were followed for an average of seven years. Those who had ever received tooth scaling (10,887) were compared with 10,989 age-, gender-, and comorbidity-matched subjects who had not received tooth scaling. The scaling group had a reduction in the rate of myocardial infarction (heart attack) from 2.2 percent in the control group to 1.6 percent. After analysis for many variables, this turned out to be a risk reduction of 31 percent.
For strokes, the risk reduction was 15 percent, and for total cardiovascular events the reduction was 16 percent. More frequent tooth scaling was correlated with an even greater risk reduction for all three measures. However, this is not the end of the controversy.
The American Heart Association recently issued a statement that says no convincing evidence exists to link untreated gum disease with either heart disease or stroke. This statement is endorsed by the American Dental Association and the World Heart Federation. (Lockhart PB, et al., Periodontal disease and atherosclerotic vascular disease: does the evidence support an independent association? Circulation 2012; 125:2520-2544.) The problem with any conclusions is the presence of confounding variables. Smoking, poor diets, diabetes, and age are all associated with both gum disease and heart disease. Apparently, teasing them out has been difficult in some studies, thus the controversy.
However, the above study did account for the variables and was a prospective study that was just published, so I doubt that the AHA or ADA has included this data in producing their statement, which has been in the works for three years. Treatment of your gums might not be a treatment for heart disease, but it is likely to be a helpful preventive measure, and at the very least, it will improve your dental health. Interestingly, Taiwan’s national healthcare program pays for tooth scaling, whether or not a person has severe gum disease.
Zinc supplements have been the subject of study for the prevention and treatment of viral illnesses, particularly of the common cold, and the results have been sometimes conflicting and often controversial (the antagonism to supplements in the medical community can be intense). A new study shows that zinc can provide some benefit for symptoms of viral respiratory infections.
Researchers looked at all published randomized controlled trials through 2011 comparing oral zinc with placebo or no treatment. They found 17 trials with a total of 2121 participants. Compared with those given placebo, those who received zinc had a shorter duration of cold symptoms. The average was 1.65 fewer days of symptoms. This benefit was not seen in children, but for adults they found 2.63 fewer symptom days. (Science M, et al., Zinc for the treatment of the common cold: a systematic review and meta-analysis of randomized controlled trials. CMAJ. 2012 May 7. [Epub ahead of print].)
This may not seem like a lot, but it is very significant because the common cold is, well, so common (62 million cases per year). When you consider the number of days of work lost and the discomfort of cold symptoms, it is a great benefit to individuals and to society to reduce adult cold symptoms by even one day, so 2.63 days is a great result. Critics say for such a small benefit the side effects are not worth it, but in the larger picture the benefits are not small, and the side effects that they are talking about are relatively minor: a bad taste in the mouth, a metallic taste, and digestive upset. I think these are small prices to pay for shortened colds (and most people do not have such side effects).
Coffee is one of the most widely consumed beverages in the world. I generally do not recommend it because of its stimulant effects (and post-caffeine depression), digestive disturbances (acid indigestion or reflux symptoms), elevated blood pressure, increases in the serum levels of LDL-cholesterol, and worsening of fibrocystic breast disease (possibly related to caffeine). In addition, coffee is often from countries that do not strictly regulate pesticide use. If you do consume it, choose organic, Fair Trade Certified products, and preferably those with Rain Forest Alliance certification. I also suggest decaffeinated coffee that is processed without chemicals, as is all organic decaf.
However, the data on coffee’s effects on overall mortality have been either favorable or neutral in earlier studies. Those studies have not always been well controlled for other variables, such as smoking, obesity, and diabetes, but they have found that serum markers of inflammation and insulin resistance are lowered by coffee. This is likely due to the rich content of antioxidants and beneficial phytochemicals, other than caffeine. Recent large studies have suggested benefits from coffee consumption.
A new report uses data from the NIH-AARP Diet and Health Study to determine the association of coffee consumption with total and cause-specific mortality. They started with 617,119 AARP members 50 to 71 years old and after exclusions for various reasons ended up evaluating 229,119 men and 171,141 women. The exclusions consisted of over 126,000 subjects who had heart disease, cancer, or a previous stroke at the start of the study. In addition to detailed lifestyle and diet questionnaires, they asked about caffeinated or decaffeinated coffee consumption.
The subjects were followed for 13 years, making 5,148,760 person-years of follow-up, during which time 33,731 men and 18,784 women died from a variety of causes. In the raw age-adjusted models, coffee drinkers had an increased risk of death. However, they were also more likely to smoke, and after adjustment for tobacco-smoking status and other variables, coffee consumption was associated with significantly lower mortality. It was not a large benefit, but with the number of participants it was highly statistically significant. (Freedman ND, et al., Association of coffee drinking with total and cause-specific mortality. N Engl J Med. 2012 May 17;366(20):1891-904.)
Compared to those men who never drank coffee, those who drank 1 cup per day had a 6 percent reduced all-cause mortality, for 2-3 cups it was a 10 percent decline, and for 4-5 cups it was a 12 percent decline. For 6 or more cups there was only a 10 percent reduction in mortality, reversing the trend of dose-related benefits. For women, the declines were 5 percent, 13 percent, 16 percent, and 15 percent, indicating the same, but stronger, dose relationship.
These associations were true for heart disease, respiratory disease, stroke, injuries, accidents, diabetes, and infections, but not for cancer mortality. Heavy coffee drinking among men was associated with a small increase in cancer mortality. The authors indicated that they could not determine whether coffee was causally related to the benefits or just associated with them. They also indicated that the benefits were the same for decaffeinated coffee as for regular, so decaf would be the better choice.
Other findings indicated that compared to non-drinkers, coffee drinkers were more likely to smoke cigarettes, drink more than three alcoholic beverages per day, and consume red meat. They also tended to have a lower level of education, less participation in vigorous physical activity, and lower consumption of fruits and vegetables. About two thirds of coffee drinkers reported consuming mostly caffeinated coffee.
Some confounding issues are that the coffee intake was self-reported at one point in time and might not reflect long-term intake, and the method of preparation was not considered; some methods might adversely affect levels of beneficial compounds. When I have coffee at home, it is always organic, Fair Trade coffee prepared with a French press. If you go to a coffee shop, ask for organic, Fair Trade, decaf and see what they say. If they do not have it, consider going elsewhere, or at least suggest that they carry this kind of coffee in the future. It is increasingly available because of customer requests. I now know of three coffee shops in New Hampshire that carry organic, Fair Trade coffee. It is better for your health and better for the environment.
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