Monday, September 28, 2009

Go To Health - Chocolate

The first people known to have made chocolate from the cacao tree were members of the ancient cultures of Mexico and Central America. The Maya and Aztec people took the tree from the rainforest - they harvested, fermented, roasted and ground the seeds into a paste. When mixed with water, chile peppers, cornmeal and other ingredients, this paste made a frothy spicy chocolate drink. The word ‘chocolate’ comes from a combination of the terms ‘choco’ (foam) and ‘atl’ (water).

*Nitric Oxide (NO) Dr. Norman Hollenberg at Harvard University has studied the ability of cocoa to increase the amount of nitric oxide (NO) in the body. NO is a gaseous ‘signaling molecule’ that crosses membranes and freely diffuses between cells. It signals the muscular coating around arteries to relax, thus improving blood flow and lowering blood pressure. Several medicines are based on this effect - nitroglycerin is a vasodilator because it is converted to NO in the body and Viagra stimulates erections by the effects of NO on blood vessels in the penis. Another protective effect of NO on the cardiovascular system is its inhibition of blood clotting and the adhesion of white blood cells on the lining of blood vessels.

*Flavonoids – Flavonoids are a group of compounds found widely in plants that produce healthy effects on animals who eat them. Many flavonoids activate the nitric oxide system. Cocoa is one of the richest sources of flavonoids (although current processing techniques reduce the content), Dr. Hollenberg and colleagues in Panama studied the Kuna Indians who live off the coast of Panama; the Kuna drink lightly processed cocoa as their main beverage and therefore have one of the world’s richest diets in flavonoids. The Kuna do not show an increase of blood pressure with aging, or decline in kidney function. Their death rates from heart disease, stroke, diabetes and cancer are markedly lower than those of genetically similar Kuna in mainland Panama, where cocoa is replaced by local foods. The researchers wrote a paper on the Kuna, concluding that “the comparatively lower risk among Kuna in the San Blas islands from the most common causes of morbidity and mortality in much of the world, possibly reflects a very high flavanol intake and sustained nitric oxide synthesis activation. However, there are many risk factors and an observational study cannot provide definitive evidence.”

In the Dutch Zutphen Study, cocoa intake specifically was associated with a 50% reduced risk of cardiovascular mortality between the highest and lowest quintile of intake in 470 elderly men. These epidemiologic data led to the hypothesis that the health benefits of cocoa may be linked to its flavonoids. Both the flavanoid content and the total antioxidant capacity have been shown to increase in plasma after cocoa consumption.

*CocoaVia by Mars The Mars company has been studying the health benefits of chocolate for over a decade, and have isolated the particular flavonol in cocoa that relaxes blood vessels and inhibits clotting. Their formula for this - a trade secret - is in their chocolate bar CocoaVia, along with plant substances (sterols) that lower cholesterol. But there’s a big catch, reports the Harvard Heart Letter - the extra calories and saturated fat in these bars make them less desirable as a daily source of flavonols. A product called ‘Acticoa’ in Europe is said to have the same beneficial ingredients as the Mars bars, but is not available in the US.

*Theobromine Chocolate has a mild stimulating effect due to theobromine, a substance similar to caffeine. People sensitive to caffeine and parents of young children should be cautious about this, and avoid chocolate close to bedtime.

*Healthy Chocolate for You! You can buy organic, fair trade, unsweetened cocoa powder at natural food stores and some supermarkets. Make a cocoa drink with soy milk, 1% milk or hot water, and sweeten it with xylitol (a healthy sugar that’s good for your teeth!) or stevia or both. You can skip sugar by mashing a banana with unsweetened cocoa powder, and add peanut butter if desired. You can make a shake with your favorite ingredients and add cocoa powder and pomegranate concentrate for sweetness. Purists can buy organic, fair trade cocoa nibs and eat them with raisins for sweetness. Buying ‘fair trade’ cocoa or chocolate bars is important, because cocoa producers in Latin America are often badly underpaid and in Africa child labor is a serious problem. The fair trade label ensures that the cocoa workers are decently treated.

Sadja Greenwood, MD MPH, back issues on this blog

Monday, September 21, 2009

Go to Health - Vitamin D Update

The vitamin D story begins with the evolution of human skin color in Africa. The current hypothesis is that early humans had more of the dark pigment melanin in their skins to provide protection against intense sunlight. But melanin can also block the ultraviolet radiation that triggers vitamin D production in the skin. In Africa, we humans produced the right amount of Vitamin D for our health. As we migrated out of Africa to live at higher latitudes, natural selection favored those with lighter skin, who could absorb more vitamin D from sunlight. People with darker skins were more likely to have Vitamin D deficiency and develop rickets. Women with rickets often have a deformed pelvis and have great trouble giving birth, leading to an evolutionary disadvantage. In the early 20th century (before vitamin supplementation) blacks in the US were 2-3 times more likely to suffer from rickets as whites. Dark-skinned people in higher latitudes need to be exposed to about 6 to 10 times as much sunlight as white-skinned people for the vitamin D in their blood to reach acceptable levels.

Vitamin D, formed on the skin with sun exposure, is a fat soluble vitamin essential for maintaining many body systems. Virtually all of our cells have receptors for Vitamin D. Current studies show the following:

*Osteoporotic fractures - Women who take calcium and vitamin D supplements have been shown to have a lower risk of fractures in the hip and other areas. Levels of supplementation higher than 400 IU daily were needed to achieve these results. D also helps to prevent tooth loss.

*Muscle strength -Vitamin D is helpful in promoting muscle strength and decreasing muscle pain. Recent studies show that vitamin D decreases falls in the elderly.

*Weight Loss - several studies show that overweight people on diets lose more weight when they take calcium and vitamin D. There is much current interest in adding Vitamin D and calcium supplements to all weight loss regimens.

*Heart disease - Low levels of D is associated with an increased risk of heart disease, high blood pressure, insulin resistance and systemic inflammation

*Cancer – a study from University of California San Diego has shown that higher serum levels of vitamin D are associated with substantially lower rates of colon, breast, ovarian, renal, pancreatic, aggressive prostate and other cancers. The authors of this study conclude that raising serum D in the population to optimum levels (40 to 60 ng/mL) could prevent approximately 58,000 new cases of breast cancer and 49,000 new cases of colorectal cancer each year, and three fourths of deaths from these diseases in the United States and Canada, (This is an astounding theory, and if even partially true it could prevent a great deal of suffering.)

* Autoimmune disease Adequate vitamin D levels may decrease the risk of autoimmune diseases such as type 1 diabetes, multiple sclerosis and rheumatoid arthritis.

* Memory loss with aging A recent English study showed that seniors with the lowest levels of vitamin D were twice as likely to have cognitive impairment (memory, attention span and orientation in time and space) as those with the highest levels of vitamin D. A study from Tufts University in Boston showed that seniors with higher levels of vitamin D did better with planning, organizing and thinking abstractly, and also were less likely to show damage to small blood vessels in the brain.

*Respiratory infections people of all ages with low levels of D are more at risk for colds and other respiratory infections, including tuberculosis. This finding is more important in the current flu season.

*Seasonal affective disorder (winter blues) and depression - Studies are beginning on the use of Vitamin D for SAD, which may be more effective than light therapy.

*Vitamin D deficiency in the US More than 75% of Americans have less than optimum levels of D according to a nationwide nutrition study from 2001-2004. Increasing skin protection from sunburns, less outdoor activity, and declining milk consumption may explain the decrease. Also low levels of vitamin D are associated with obesity, which has been increasing in this country.

How to get enough Vitamin D - Since Vitamin D plays such an important role in health, what should you do to protect yourself? You can start by having your health care provider order a test for a blood level of 25 hydroxy vitamin D. A level above 30 ng/ml is desirable, and 40-60 ng/ml is considered optimum. To achieve this level without high sun exposure, which can carry risks of skin cancer and skin aging, most adults in our area need to supplement with at least 1000 IU daily, and may need more. You can increase this amount until you have the desirable blood level of D. If getting a blood level for D is not practical for you, you will be safe with 1000-2000 IU daily. The researchers at UCSD (see above - Cancer) suggest 2000 IU daily, and affirm its lack of risks.. We form very little Vitamin D on our skin between October and March at this latitude. People with darker skin absorb Vitamin D from the sun more slowly, and may need higher levels of supplementation.

: Sadja Greenwood, MD, MPH –back issues at on this blog

Monday, September 14, 2009

Go to Health: Oats

Oats have been grown for human food and for livestock since ancient times. In Samuel Johnson's dictionary, oats were defined as "eaten by people in Scotland, but fit only for horses in England." The Scotsman's retort "That's why England has such good horses, and Scotland has such fine men.”

The Hype on Oats & Cholesterol: After the publication of several articles in the 1980’s on the value of oats to lower cholesterol, oat products from candy bars to pasta to chips were promoted with exaggerated claims for health and weight loss.

The Evidence: Oats contain more soluble fiber than other grains; a soluble fiber called beta-glucan is especially valuable, and is found in oats, barley, yeast and certain mushrooms. Beta-glucan in yeast and mushrooms has been found to have favorable immune-enhancing effects. Studies are incomplete on similar effects from eating oats. In 1997, the FDA said that "a diet high in soluble fiber from whole oats (oat bran, oatmeal and oat flour) and low in saturated fat and cholesterol may reduce the risk of heart disease". The FDA had reviewed 37 studies in which oats were consumed as hot and cold cereals or used in a variety of other foods - muffins, breads, shakes, and entrées. It was concluded that about 2/3 cup of oatmeal daily would provide the beta-glucan to achieve a clinically relevant decrease in serum total cholesterol concentrations. Most studies have shown a reduction of total cholesterol and LDL cholesterol of 7 to 10% . The soluble fiber in oats appears to reduce the absorption of cholesterol in the intestines. (Soluble fiber with similar effects on cholesterol are found in barley, dried beans, apples, pears, prunes and psyllium seed).

Blood Sugar: Oat fiber has also been shown to lower levels of blood sugar after a meal, making it a good food for people with diabetes. The reduction of the glucose and insulin peak after eating the soluble fiber in oats occurs because oat digestive products in the stomach and small intestine are more viscous, which retards their absorption into the bloodstream.

Inflammation: whole oats contain a beneficial polyphenol (a class of antioxidant compounds found in most plant foods) called Avenanthramides (AV) . Unique to oats, AV interferes with inflammation and the development of plaque on the arteries. Moshen Meydani at the Vascular Biology Laboratory at Tufts University studied AV and found that adhesive molecules cause blood cells to stick to artery walls. Inflammation results, leading to a buildup of plaque that narrows the artery. The suppression provided by the AV in oats may allow better blood flow.

Skin protection: Oatmeal has been used since Roman times or longer to relieve itch and skin irritation. Recent studies show that AV in oats inhibits inflammation in skin cells when applied topically. Itching and scratching are suppressed. AV has been found to be effective in reducing the redness of sunburn when used in the 24 hours after a burn. It will give temporary relief to the itching of poison oak and poison ivy. The use of oatmeal products on the skin as an anti-irritant has potential in the care of infants, people with sensitive skin, sunburns and itchy, dry skin. You can make your own soothing oatmeal bath to relieve skin itching and inflammation by grinding a small amount of rolled oats in a blender; put the resulting flour into a a cheesecloth bag and run warm tap water through it for a bath. Many oatmeal-derived products are available commercially; ask your pharmacist for advice. .

. Sadja Greenwood, MD –back issues at


Monday, September 7, 2009

Go To Health: Flaxseed

Flax has been grown since the beginnings of civilization, initially in Babylon & Egypt. It was used to make linen for clothing, fishnets, and to wrap mummies. In the 8th century, Charlemagne commanded his subjects to eat flaxseed to maintain good health. In the 12th century, Abbess Hildegard von Bingen used flaxseed poultices to treat boils. Throughout history it has been used to treat constipation, as a bulking agent, combined with plenty of water. While it is still used today to make linen and as a healthy human food, flax is also made into industrial linseed oil, linoleum, and animal feed.

*Flaxseed oil: The oil in flax seeds contains alpha-linolenic acid (ALA), an essential omega-3 fatty acid like fish oil. ALA may not have the same benefits as fish oil (see my blog on omega-3 fatty acids), as it is more difficult for the body to efficiently convert ALA to a form of omega-3 fatty acids that it can readily use –the EPA and DHA in fish oil. However, ALA is a good choice for vegetarians. Flaxseed oil should come in a dark and opaque container and be refrigerated; add it to salad or foods after cooking. It cannot withstand high heat.

*Flaxseed Meal: When you buy whole flax seeds, grind a week’s supply and refrigerate the flax meal. You can eat it on salad, cereal or in smoothies. By eating the whole ground flax seed you are getting the oil as well as beneficial compounds known as lignans. Lignans are plant compounds similar to estrogen that also act as antioxidants. Lignans may lower estrogen in humans by inhibiting enzymes that are involved in estrogen production; the exact mechanisms are not known. There is interest in flaxseed because of the potential for plant estrogens to act differently from the body’s natural estrogen. In animal and preliminary human studies, flax seeds have been shown to inhibit tumors.

Breast Cancer: Researchers at the University of Minnesota studied the effect of flaxseed supplementation in a group of 28 postmenopausal nuns - chosen because of their strict dietary practices. The volunteers were given daily dietary supplements of either zero, five or ten grams of ground flaxseed for seven week cycles over the course of a year. A heaping tablespoon of ground flax weighs about 10 grams. Consumption of five or ten grams of flax significantly decreased blood levels of certain types of estrogen that are characteristic of postmenopausal women. Since previous studies have shown that increased levels of these estrogens (estrone sulfate and estradiol) may increase a woman’s risk of developing breast cancer, reducing levels of these hormones is thought to be advantageous. This study does not show that flaxseed prevents cancer, the researchers caution. Further studies are needed to work out how the supplement lowers estrogen and also to see if flaxseed may inhibit cancer. Besides lignans, the fiber and omega-3 fatty acids in flaxseed could also be protective.

Prostate Cancer A recent study at The M.D. Anderson Cancer Center looked at prostate cancer patients at least 21 days before surgery, and found that proliferation (cancer cell division) was significantly lower in men given supplemental flax seed – 3 tablespoons daily. These findings suggest that flaxseed is safe for men and is associated with biological alterations that may protect against prostate cancer. Previous studies had shown that ALA might not be advisable for men with prostate cancer. Further studies would be helpful on this important subject.

Blood Fats: An international review of studies on the effects of flaxseed meal on cholesterol found that flax significantly reduced total and LDL cholesterol, with the greatest effects seen in people with high cholesterol readings and in post-menopausal women.

Hot Flashes A study at the Mayo Clinic looked at 29 women with bothersome hot flashes who did not want to take estrogen because of the possible increased risk of breast cancer. After six weeks of ground flaxseed therapy, 2 tablespoons daily, their frequency of hot flashes decreased 50 percent, and the overall hot flash intensity decreased an average 57 percent. Participants also reported improvements in mood, joint or muscle pain, chills and sweating; which significantly improved their quality of life. This is an example of the ability of plant estrogens to act as an estrogen as well as an anti-estrogen.

Sadja Greenwood MD, MPH –back issues on this blog