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April 2007

Lignans and breast cancer
Fruits, meats, and colon cancer
Flavonoids lower heart deaths
Second hand smoke risks
Alcohol, aneurysm, and breast cancer
Meat protein and endometrial cancer
Ask Dr. J: Ipriflavone and hormones

Lignans and breast cancer

Lignans are estrogen-like compounds found in plant foods such as seeds, nuts, fruits, vegetables, whole grains, and beans. Lignans (plant-based estrogens) from non-soy sources are far more common in the Western diet than those from soy foods. Flax and sesame seeds contain the far more lignans than most other good sources. Flax seeds contain 85 mg per ounce, and sesame seeds contain 11 mg per ounce, while other food sources contain less than 1 mg per serving.

A study from France, published in the Journal of the National Cancer Institute, shows that post-menopausal women who consume large amounts of lignans have a lower risk of breast cancer. Risk reduction was 17 percent for women with the highest lignan intake (greater than 1.4 mg per day) compared to those with the lowest intake. (Touillaud MS, et al., Dietary lignan intake and postmenopausal breast cancer risk by estrogen and progesterone receptor status. J Natl Cancer Inst. 2007 Mar 21;99(6):475-86.)

This study involved 58,049 post-menopausal women followed for an average of 7.7 years. Over that time there were a total of 1469 cases of diagnosed breast cancer. Earlier studies were unclear on the relationship of lignans to breast cancer, but in this study, they are clearly helpful in this age group.

After flax and sesame seeds, the best sources of lignans are brassica family foods (kale, broccoli, and cabbage), apricots, strawberries, and whole grains. These lignan-rich foods are also high in fiber, vitamins, minerals, antioxidants, and other phyto-chemicals that protect against heart disease and other cancers.

Fruits, meats, and colon cancer

Polyps in the colon are benign growths that have a tendency to lead to malignancies. Larger polyps are more likely to harbor malignant cells. A new study shows that a diet high in fruit and low in meat appears to protect against the development of colorectal polyps and cancers. In this study, vegetables or moderate reduction of meat in the diet did not appear to offer the same protection as the high-fruit, very-low-meat combination. Other studies have also shown an association of meat eating with colon cancer.

Researchers at the University of North Carolina evaluated 725 patients who had just had colonoscopies. Those who ate large or moderate amounts of meat had a 70 percent greater risk of having polyps found during the examination, compared to those who ate a lot of fruit and very little meat. (Austin GL, et al., A diet high in fruits and low in meats reduces the risk of colorectal adenomas. J Nutr. 2007 Apr;137(4):999-1004.

Flavonoids lower heart deaths

Flavonoids are plant pigments that have antioxidant activity and other healthful properties, including reducing both LDL cholesterol levels and inflammation. A wide variety of these phytochemicals (also called bioflavonoids) is found in many plant foods. The Iowa Women’s Health Study reports that women who had the highest intake of flavonoids had a lower risk of death from heart disease and a lower incidence of heart and blood vessel diseases.

The study evaluated 34,489 women over 16 years and specifically looked at intake of three kinds of flavonoids – anthocyanins, flavones, and flavanones. Specific foods that were helpful included bran from whole grains, apples, red wine, pears, strawberries, and grapefruit. (Mink PJ, et al., Flavonoid intake and cardiovascular disease mortality: a prospective study in postmenopausal women. Am J Clin Nutr. 2007 Mar;85(3):895-909.) Risk reduction ranged from 10 to 22 percent. Although this may seem small, reducing heart deaths by this amount could prevent 50 to 100,000 deaths per year in the United States. Also, adding many small benefits through health habit changes gives you much greater control of your health future.

Second hand smoke risks

While I am skeptical of the value of many meta-analysis studies (a review of other studies) they are useful on the occasions when they provide confirmation of the weight of other evidence or new insights. A meta-analysis of the dangers of second-hand smoke (environmental smoke) shows that non-smokers exposed to such smoke have a 24 percent increase in lung cancer risk.

Long-term exposure (30 years) led to a 50 percent increase, and those considered to be heavily exposed to the smoke of others (restaurant and bar workers) have a 100 percent greater risk of developing lung cancer than non-smokers. Researchers evaluated studies from many countries (Stayner L, et al., Lung cancer risk and workplace exposure to environmental tobacco smoke. Am J Public Health. 2007 Mar;97(3):545-51.) Passive exposure to tobacco smoke is also associated with asthma and other respiratory ailments.

Alcohol, aneurysm, and breast cancer

The wall of the aorta where it passes through the abdomen is sometimes weakened and bulges out to form an aneurysm. This is usually the result of atherosclerosis, and leads to a life-threatening risk of rupture. A new study shows that moderate alcohol consumption (two drinks a day) is associated with an increased risk of developing such aneurysms. (Wong DR, et al., Smoking, hypertension, alcohol consumption, and risk of abdominal aortic aneurysm in men. Am J Epidemiol. 2007 Apr 1;165(7):838-45.)

This Harvard study of 39,352 men for 16 years showed that the aortic aneurysm risk was 21 percent higher when considering alcohol use at the start of the study. When evaluation of alcohol consumption was updated every four years, the risk was 61 percent higher than for non-drinkers.

Another Harvard study shows that as little as one drink per day increases a woman’s risk of invasive breast cancer by 9 percent, while two drinks per day (other than red wine) increases the risk by 43 percent. (Zhang SM, Alcohol consumption and breast cancer risk in the Women's Health Study. Am J Epidemiol. 2007 Mar 15;165(6):667-76.) This is data from the Women’s Health Study of 38,454 subjects followed for an average of 10 years.

Meat protein and endometrial cancer

The evidence for the value of reducing or eliminating meat from the diet is pretty clear by now, and it keeps accumulating. A study from Shanghai, China showed that the women who consumed the most protein from animal sources had double the risk of endometrial cancer as women who consumed the least animal protein. High levels of animal fat in the diet boosted the risk by 50 percent. High total calorie intake was also associated with greater risk. (Xu WH, et al., Nutritional factors in relation to endometrial cancer: a report from a population-based case-control study in Shanghai, China. Int J Cancer. 2007 Apr 15;120(8):1776-81.)

On the other hand, women who consumed most of their protein from vegetable sources cut their risk by 30 percent. The study compared 1204 women with newly diagnosed endometrial cancer with 1212 healthy women. Saturated fat was related to increased risk, but no association was found with polyunsaturated fats. The researchers also found that vitamins A, C, and E, as well as fiber and beta-carotene all reduced the risk, whether they were derived from food or supplements.

Ask Dr. J: Ipriflavone and hormones

Q: I have been told to take ipriflavone to improve my bone density, but I am concerned about risks. Will I need to take progesterone to protect against uterine cancer?

L.B. California, via email

A: Ipriflavone is similar to soy isoflavones but has been modified to increase its beneficial effect on bone. Depending on the studies you look at it appears to help rebuild bone or at least to halt the progression of bone loss. However, even though it has some similarities to plant-derived estrogens, it does not have estrogenic effects in the body. I have seen only one side effect reported, which is a lowered white blood cell count in a few patients. Whether this is clinically significant is not clear.

Natural bio-identical progesterone (not the synthetic derivatives that until recently have been heavily prescribed) is a very safe hormonal treatment. Even if you don’t need it because of the ipriflavone, it may still be worth taking. In itself it helps to maintain bone density. Therefore it can work quite well with ipriflavone to support the bones.

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From September to June, I see patients in New Smyrna Beach, Florida.
Call 386-409-7747, or send an email to to make arrangements.

In summer, I have a variable schedule, and I see patients in offices at the
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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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