Sunday, September 25, 2011

News about Coffee

Positive news about caffeine and coffee is on the rise! Annia Galano, a Cuban chemist, recently published a paper suggesting that coffee is one of the richest sources of healthful antioxidants in the average person’s diet. It scavenges free radicals that can have damaging effects on the body. Here is a summary of recent research.

Cognitive decline: A study by French neuropsychologist Karen Ritchie found that women over age 65 who drank over three cups of coffee a day showed less cognitive decline over 4 years than those drinking one cup or less. No such relationship was found for men in this study. A study in mice at the University of South Florida found that caffeinated coffee increases a growth factor called GCSF (granulocyte colony stimulating factor) . GCSF improves memory performance in Alzheimer’s mice, acting to remove harmful beta-amyloid protein that initiates the disease. GCSF also creates new brain connections and increases the birth of new neurons. Decaf coffee and caffeine alone did not give this protection.

Heart disease: While coffee may increase blood pressure in certain people, it can also increase blood vessel elasticity. If your blood pressure is high, it is important to assess the effects of coffee with a home blood pressure cuff and a talk with your doctor. Researchers in the Netherlands found that people drinking 2-4 ups of coffee daily had a 20% lower risk of heart disease, and a slightly reduced risk of death from heart disease and all other causes.

Reduced stroke risk: A study from Sweden’s Karolinska Institute found that women who drank one or more cups of coffee a day had a 22% lower risk of stroke – both the kind from arterial blockage and from bleeding in the brain. Men were not included in this study, as the population of 35,000 women were in a mammography study.

Breast cancer risk: Another Swedish study showed that drinking coffee specifically reduces the risk of estrogen-receptor negative breast cancer. There has been speculation that the boiled coffee used by Swedes has more beneficial compounds against cancer than the filtered coffee preferred in this country, but this remains an unproven question. Boiled coffee can increase cholesterol levels.

Prostate cancer risk: A recent study from Harvard School of Public Health of 48,000 male health professionals showed that men who drink coffee (regular or decaf) had a lower risk of developing a lethal form of prostate cancer. Men consuming 6 or more cups daily had a 20% lower risk of developing any form of prostate cancer. They had a 60% lower risk of developing lethal prostate cancer. Drinking 1-3 cups daily was associated with a 30% lower risk of lethal prostate cancer. Additional studies of the mechanisms involved are underway.

Diabetes risk: Past studies have suggested that regular coffee drinking may reduce the risk of type 2 diabetes. At the University of Nagoya in Japan, lab mice commonly used to study diabetes were fed either water or coffee. Coffee consumption prevented the development of high blood sugar and improved insulin sensitivity. There were also beneficial changes in inflammation and fatty liver. Caffeine was felt to be the anti-diabetic compound. However, another recent study from Duke University found that in humans, caffeine can increase insulin resistance in people without diabetes , and produce an exaggerated blood glucose spike in diabetics after they eat carbohydrates. More research needed here.

Gout: A Harvard study of male health professionals looked at 46,000 men over age 40 with no history of gout. After controlling for risk factors for gout, they found that men who drank 4-5 cups of coffee daily had a 40% lower risk of gout, and those drinking 6 or more cups had a 59% lower risk. Decaf coffee showed a more modest lower risk. Tea drinking had no effect on gout, and factors other than caffeine were believed responsible for the benefit.

Coffee makes most users feel energetic, and for many people it is a great pleasure. However, the caffeine in coffee can be a big problem for people with irregular heart rhythms, insomniacs and children. These recent studies should help to clarify what to do with this amazing beverage. Consult your body and your medical history; use it wisely.
Sadja Greenwood, MD, MPH back issues on this blog

Saturday, September 17, 2011

Go to Health: News about Walnuts & Cranberries

Walnuts – Breast and Prostate Cancer:
Dr Elaine Hardman, at Marshall University School of Medicine in West Virginia, has been investigating diet and cancer for years. She noted that walnuts contain multiple ingredients that slow cancer growth, including omega-3 fatty acids, antioxidants, and phytosterols (healthy compounds in plants that are similar to cholesterol, and reduce cholesterol in humans). Hardman worked with mice that are genetically likely to develop breast cancer at high rates. She studied mice given walnuts during pregnancy through weaning, and then the pups were fed a walnut supplemented diet. These mice developed breast cancer at less than half the rate of a group on a typical lab-mouse diet. Additionally, the number of tumors and their sizes were smaller. Gene analysis showed that those on the walnut diet had different expression of genes associated with the breast cancers in mice and humans. The amount of walnuts fed to the rats would correspond to about 2 oz. daily in humans. One cup of walnut halves is about 3 1/2 ounces. Hardman also found that increases in omega-3 fatty acids did not fully account for the anti-cancer effect, and that tumor growth decreased when dietary vitamin E increased. Dietary vitamin E is found in nuts, sunflower seeds, spinach and other leafy vegetables, and many natural foods.

Dr. Paul Davis at UC Davis has studied the benefits of walnuts in mice genetically programmed to develop prostate cancer. When he compared 8 week pups given added walnuts to control pups given added soy oil, those in the walnut group had cancers 30-40% smaller. They also had reductions in several proteins that may increase cancer growth, including insulinlike growth factor-1. Davis said the amount of walnuts humans should eat to correspond to the mouse diet was about 2.4 ounces daily.

Walnuts also contribute to heart health, by decreasing LDL cholesterol, lowering the risk of clotting, and decreasing inflammation. Numerous studies have shown that they do not cause weight gain, but rather make people less hungry for other high-fat, sugary foods.

Cranberries- Blood vessel flexibility and infection prevention:
Researchers at Boston and Tufts Universities recently reported that people with heart disease (coronary artery disease) showed a decrease in the stiffness of the aorta after drinking double-strength cranberry juice. Blood vessel dilation and blood flow to the arms also improved, but in an uncontrolled pilot study. Subjects drank 16 ounces of a cranberry drink that was 54% cranberry juice daily. Authors of the study point out that the flavonoids in plant foods have multiple benefits. Flavonoids are plant pigments that that have anti-inflammatory, anti-microbial and anti-cancer activities. In the case of cranberries, the heart benefits are added to known anti-bacterial benefits. A recent study that looked at daily cranberry pills compared to antibiotics to prevent bladder infections in women. Those taking the antibiotic (Bactrim) had the fewest bladder infections, although the cranberry pills were also effective. However, women taking the antibiotic developed resistance to Bactrim and other antibiotics. Cranberries are believed to be helpful by preventing bacteria from sticking to the walls of the bladder and urethra and multiplying.

Rather than taking cranberry pills, it is probably better to drink the whole juice on a daily basis, for heart health (if you have narrowed arteries), or to prevent frequent bladder infections. Note – people on Coumadin should not drink cranberry juice without talking to their doctor – it can increase the risk of bleeding. For all other interested people, I suggest looking for an unsweetened cranberry concentrate, which you can usually find in health food stores. Mix it with water, add a little apple juice for sweetener or put it in your shake. Some people love its sour taste. Fall is coming, and whole cranberries will be in the market soon!
Sadja Greenwood, MD MPH back issues on this blog