Atrial fibrillation, diet, and caffeine
Soluble fiber for irritable bowel
Fruits provide more health benefits
Vitamin D-more health benefits
Mediterranean diet helps depression
Soy foods reduce hip fractures
Fish, shellfish, and diabetes risk
A report from the European Society of Cardiology shows that a diet high in caffeine increases the likelihood of developing atrial fibrillation, an arrhythmia that can lead to shortness of breath, palpitations, and fatigue. If untreated, it can increase the risk of stroke. Subjects in this study were found to be more likely to have atrial fibrillation if they ate more red meat and dairy products. If they adhered more closely to the Mediterranean diet, they were less likely to develop atrial fibrillation.
Those subjects who consumed higher levels of caffeine from coffee, colas, tea, and cocoa had a higher risk of developing atrial fibrillation. This increased risk was lower if those consuming higher levels of caffeine also followed the Mediterranean diet more closely. With this diet, consumption of red meat and meat products is rare, and dairy consumption is low.
They considered that coffee or equivalent consumption was low if it was 1 cup per day, medium was 2-3 cups per day, and high intake was more than 3 cups per day. (Mattioli, AV, High caffeine intake can lead to arrhythmias. Press Release, ESC Congress 2009, August 30, 2009)
Irritable bowel syndrome (IBS) is a collection of symptoms that include gas, bloating, alternating diarrhea and constipation, and abdominal pain or discomfort. (These symptoms are similar to inflammatory bowel disease (IBD), but without the accompanying inflammation and bleeding.) In the past, usual dietary recommendations were to avoid fiber foods in the diet. However, this leads to a poorer quality diet that eliminates fresh fruits and vegetables and whole grains.
In my experience, a whole, natural foods diet leads to fewer symptoms of IBS. New research shows that bran (an insoluble fiber) led to only minor improvement in symptoms that was not statistically significant. However, soluble fiber (in this study, psyllium seed powder) led to a 90 point reduction in symptom score (Bijkerk CJ, et al., Soluble or insoluble fibre in irritable bowel syndrome in primary care? Randomised placebo controlled trial. BMJ. 2009 Aug 27;339:b3154. doi: 10.1136/bmj.b3154.)
Soluble fibers are found in a variety of healthy whole foods, including beans, oats, barley, psyllium and flax seeds, eggplant, okra, potatoes, sweet potatoes, carrots, and broccoli, and fruits, such as bananas, berries, apples and pears (excluding the skins). Fiber is often neglected in food because it is not digested or metabolized, but it is an important component of the diet.
In this research, 275 patients, aged 18 to 65 years, were divided into three groups (soluble fiber, insoluble fiber, and placebo), and treated for 12 weeks with twice daily powder supplements. They were evaluated at the end of each month for symptom severity scores.
Fruits and vegetables have many known benefits, and they are rich in a variety of phytochemicals, such as flavonoids, polyphenols, and other antioxidants that apparently protect from chronic degenerative diseases. New research has found that the levels of these beneficial substances have been markedly underestimated by previous analytical methods.
The new methods have found that apples, peaches, and nectarines have up to five times more polyphenols than was thought. These include catechins, proanthocyanidins, and ellagic acid. The cell walls of these fruits are not broken down easily, so prior research only evaluated easily “extractable polyphenols” rather than totals.
However, when treated with acids (such as are found in digestive juices), these cell walls released far more of the beneficial chemicals. (Arranz S, et al., High Contents of Nonextractable Polyphenols in Fruits Suggest That Polyphenol Contents of Plant Foods Have Been Underestimated. J Agric Food Chem. 2009 Jul 28. [Epub ahead of print])
It is important to eat whole foods, and in some cases it is even beneficial to slightly cook the foods to increase the release of the phytochemicals stored in the cell walls (this is true, for example, with carotenoids found in carrots). However, digestion should release the full value of many of these foods.
Low vitamin D levels are associated with a higher risk of developing a number of diseases. A Finnish study of 6219 adults over 30 with no vascular disease at baseline, followed for 26 years, showed that those subjects with the highest level of vitamin D in the serum had a markedly lower risk of death from stroke compared with those subjects with the lowest levels. (Kilkkinen A, et al., Vitamin D status and the risk of cardiovascular disease death. Am J Epidemiol. 2009 Oct 15;170(8):1032-9.
Another study shows that higher levels of vitamin D help with melanoma the deadliest from of skin cancer. In this prospective study of patients with melanoma, those with higher levels of vitamin D in the blood had thinner skin tumors on average and a 20 percent improvement in relapse-free survival. (Newton-Bishop JA, Serum 25-Hydroxyvitamin D3 Levels Are Associated With Breslow Thickness at Presentation and Survival From Melanoma. J Clin Oncol. 2009 Sep 21. [Epub ahead of print])
The association with reduced heart disease mortality was small and not statistically significant, although other studies have found benefits for heart disease also. It should be noted that most of the subjects in this study had relatively low vitamin D levels. Recent evidence suggests that people would benefit from supplements of 1000 to 5000 IU, or even higher doses, of vitamin D3 (cholecalciferol, the natural form), not D2 (irradiated ergosterol), the manufactured form.
Eating habits that are closest to the Mediterranean diet pattern (MDP) can help with depression. In a Spanish study of 10,094 healthy participants, researchers used a food-frequency questionnaire to assess adherence to the MDP. The MDP is high in vegetables, fruits, nuts, cereal grains, beans, and fish and very low in meat, meat products, and whole-fat dairy.
Over a 4.4 year follow-up, those who adhered most closely to the MDP had about half the risk of developing depression compared to those who did not follow the MDP. (Sánchez-Villegas A, et al., Association of the Mediterranean dietary pattern with the incidence of depression: the Seguimiento Universidad de Navarra/University of Navarra follow-up (SUN) cohort. Arch Gen Psychiatry. 2009 Oct;66(10):1090-8.)
The research found particular benefits from fruits, nuts, and beans. In addition, the risk was lower for those who consumed a higher ratio of mono-unsaturated fatty acids to saturated fatty acids. (more olive oil and less animal fat).
A higher intake of soy foods in the diet appears to reduce the risk of hip fracture in post-menopausal women. Researchers followed 63,257 men and women for 8 to 13 years and placed them in four different levels of soy intake (what they called “tofu equivalents”). The subjects were 45 to 74 years old when they enrolled in the study.
Women with the lowest level of soy intake had the highest risk of hip fracture, while those in the three higher-intake groups had a 21 to 36 percent lower incidence of fractures. The benefits were not seen in men (men generally have a higher bone density than women at comparable ages). (Koh WP, et al., Gender-specific associations between soy and risk of hip fracture in the Singapore Chinese Health Study. Am J Epidemiol. 2009 Oct 1;170(7):901-9.)
The beneficial amount of tofu (or equivalents) in this study was about two ounces or more per day, on average. This is much higher than the consumption in Western countries. Soy intake in these countries tend to be more of the “texturized vegetable protein,” which is so highly processed and adulterated that it is unlikely to promote health.
Eating fish appears to lower the risk of developing type-2 diabetes, in a new study from England. However, this does not appear to be the case for eating shellfish. The researchers evaluated 21,984 men and women who were 40 to 79 years old at enrollment in the study from 1993-1997 and followed them for 10 years. (Patel PS, et al., Association Between Type of Dietary Fish and Seafood Intake and the Risk of Incident Type 2 Diabetes The European Prospective Investigation of Cancer (EPIC)-Norfolk cohort study. Diabetes Care 2009 Oct; 32(10):1857-1863.)
Eating one or more servings per week of white fish (such as cod, haddock, or sole) or oily fish (such as sardines, salmon, and mackerel) lowered diabetes risk by 25 percent. However, consuming fried fish did not lower the risk of diabetes in this study, regardless of the kind of fish. Earlier studies of fish consumption and diabetes (such as the Nurses’ Health Study) did not show the benefits seen in this study.
Eating shellfish appeared to have the opposite effect, increasing the risk of diabetes by 35 percent. This may or may not have anything to do with the shellfish specifically. These are often eaten fried or drenched in butter, or with mayonnaise type sauces, which might confound the data. However, shellfish are rich sources of dietary cholesterol, and this has in itself been associated with an increased risk of type-2 diabetes.
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