Quick Facts....
- Diet and exercise are two ways women can achieve greater bone strength
and slow down age-associated bone loss.
- Estrogen is a woman's natural protection against heart disease until
menopause.
- Women should evaluate their own health risks and discuss with their
doctor whether menopausal hormone therapy (MHT) is an appropriate choice.
- Phytoestrogens (plant estrogens) may offer protection from health
problems associated with menopause.
- Coronary heart disease (CHD) is the leading cause of death in women
over 50.
Women's health issues have been gaining wide attention and are now at the top of the health-research agenda. Scientifically supported nutrition information is being provided to help women understand ways to prevent disease and maintain health. Some advice creates more questions than it answers. Trying to sift through all the details can be overwhelming.
Questions that particularly concern women include:
- What are the benefits and risks of taking menopausal hormone therapy
(MHT) after menopause?
- Will a calcium supplement prevent osteoporosis?
- Are vitamin supplements beneficial to prevent disease?
Current nutrition research can help answer these questions and more.
Osteoporosis
Osteoporosis is a major public health problem. Women are most at risk
for developing this often debilitating bone disease. Bones become strong
as calcium and minerals are deposited from birth until around 30 years
of age. The strength of bone depends on adequate calcium intake, yet many
women don't consume enough calcium for adequate bone thickness.
After 30, bones naturally start to lose more calcium than is deposited. Therefore,
the greater the bone strength achieved by high calcium early in life,
the larger the reserve for later years. Low bone strength results in bones
that break easily, particularly the wrist, hip and back. (See fact sheet
9.359,
Osteoporosis.)
Menopause is considered a critical time for bone health. Most women experience
a rapid loss of bone mass in the first five years following menopause.
Diet and exercise are two ways that women can retain bone strength and
slow age-associated bone loss. This includes consumption of calcium-rich
foods and engaging in regular weight-bearing exercise such as jogging
or walking. While weight-bearing exercise is effective in keeping bones
strong, some women have physical limitations that prevent them from participating
in this type of activity. Menopausal hormone therapy also slows down bone
loss, however it is somewhat controversial. Discuss with your doctor whether
this is an option you should consider.
Smoking, excess alcohol, caffeine-containing beverages, some prescriptive
medications as well as a high-sodium intake, have all been shown to increase
bone loss.
| Table 1: The National Institutes of Health recommendations for calcium intakes for women. |
| Pregnant/ breast-feeding |
1,200-1,500 mg |
| Premenopausal (25-50 years old) |
1,000 mg |
| Postmenopausal taking ERT (under 65) |
1,000 mg |
| Postmenopausal not taking ERT (under 65) |
1,500 mg |
| All women over 65 |
1,500 mg |
| (An 8-ounce glass of milk supplies about 300 mg of calcium.) |
Menopause
Menopause initiates unique risk factors in women for both osteoporosis and
coronary heart disease. When a woman goes through menopause, there is
a 70 percent decline in estrogen production. Estrogen is one of two major
reproductive hormones that women’s bodies synthesize.
Besides its primary role in the reproductive cycle, estrogen plays a key role
in helping bones absorb and retain calcium. Estrogen also positively influences
women's cholesterol levels by increasing HDL, the so-called "good" cholesterol,
and decreasing LDL, the "bad" cholesterol. After menopause, the drop in
estrogen synthesis contributes to rapid bone loss, increasing the risk
for osteoporosis and higher blood cholesterol level, which in turn increases
heart disease risk.
Menopause Hormone Therapy (MHT)
Choosing a course of menopause hormone therapy, previously referred to
as hormone replacement therapy, to treat hot flashes and other menopausal
symptoms as well as to decrease the risk of osteoporosis can be a difficult
decision. There are various types of MHT, such as taking estrogen alone
or in combination with progestin, a form of progesterone. As research
on postmenopausal women expands, new risks, benefits and alternatives
to hormone treatment are being discovered.
MHT can cause complications for those who have liver, pancreatic or gallbladder
disease or suffer from severe migraine headaches. If you have had breast
cancer or have a family history of breast cancer, MHT is usually not advised.
Estrogen and progestin have their good and bad sides. While both are necessary
for reproduction, they can stimulate the growth of breast tissue and have
the potential to promote development of cancerous tumors in breast tissue.
Estrogen also stimulates endometrial growth (uterine lining) and may slightly
increase risk for endometrial cancer. However, the combined therapy of
estrogen with progestin has shown to counteract endometrial cancer risk.
In contrast to these risks, women who have a family history of osteoporosis
or other risk factors for osteoporosis may benefit from MHT. Some doctors
recommend initiating MHT with the onset of menopausal symptoms to help
debilitating osteoporosis. Ethnic background might influence the decision.
The risk for osteoporosis is higher in Caucasians. In contrast, African-American
women are rarely at risk for osteoporosis. While estrogen supplements
can delay bone mass loss, they cannot reverse or entirely prevent it.
Earlier research studies also suggested that MHT decreased coronary heart
disease (CHD) risk in postmenopausal women. However, more recent research
has indicated that taking MHT actually increases the risk for heart disease
as well as for stroke and life-threatening blood clots. Lifestyle changes
such as daily exercise and following a heart-healthy diet are more effective
in protecting against heart disease. Women need to consult with their
doctor to evaluate their other risk factors (family history, smoking,
high blood pressure, diabetes) for heart diseases in order to determine
how taking MHT may affect their risk factor for heart disease. If a woman’s
overall risk factor is very low, taking MHT to alleviate hot flashes,
improve sleep and provide an overall better quality of life may be beneficial
during menopause.
Phytoestrogens
Phytoestrogens, or plant hormones, may offer protection from symptoms and health
problems associated with menopause. If taken in large enough amounts,
plant hormones may slow the onset of osteoporosis and temper menopause
symptoms. And it appears they do this without negative side effects. Additionally,
plant hormones may help reduce the risk of breast cancer, although further
research is needed.
Three hundred plants with estrogen-like activity have been identified, including carrots, apples, dry beans, barley and oats. The highest source is soybeans.
The proposed benefits of phytoestrogens include helping to slow bone loss, lowering total serum cholesterol and raising the HDL level, reducing the thinning of vaginal tissues associated with cessation of menstruation, and lessening menopause symptoms like night sweats and mood swings.
Cardiovascular Disease
Cardiovascular disease (CVD), which includes stroke and coronary heart
disease, is the leading cause of death and disability in women. Women
differ from men in their vulnerability to CVD. Also, the risk factors
that predict cardiovascular disease risk and incidence differ in women.
Compared to men, women’s onset of heart disease (CHD) is delayed
about 10 years due to the presence of estrogen prior to menopause. Once
women reach 70, their rates for CHD mortality catch up to men’s.
However, as women age, they have a greater chance than men to develop
specific CHD risk factors, such as Type 2 diabetes mellitus, hypertension
and congestive heart failure.
The three most modifiable risk factors for CVD are cigarette smoking,
high blood pressure and high blood cholesterol. Physical activity, weight
maintenance, and a heart-healthy diet have been shown to prevent the development
of CVD. Furthermore, studies show that the benefits of taking a daily
dose of aspirin to prevent CVD outweigh the risks of side effects, such
as gastrointestinal bleeding. However, consult your physician to determine
whether or not aspirin therapy is a good choice for you and also to identify
the appropriate dose.
Breast Cancer
It is not clear whether a high-fat diet is associated with breast cancer.
Overweight or obese women are thought to be at greater risk for developing
the disease. With increased weight, there are greater amounts of estrogen
produced by the body. Just as estrogen in HRT increases breast cancer
risk, high amounts of estrogen produced by women before menopause may
also increase the risk of breast cancer. One recent study suggested the
red meat and processed meat consumption may be linked to breast cancer,
as well. However, further studies are needed to confirm this finding.
(British Journal of Cancer, April 2007-UKWCS).
Studies on breast cancer incidence reveal rates in American women are much
higher than in women of other populations. Women from Mediterranean areas,
where olive oil and fish oil comprise a large part of the diet, have less
breast cancer, even though caloric intake from fat is higher than for
American women. Also, women who live in sunnier areas tend to have a lower
incidence of breast cancer. This prompted several new studies, which indicate
that Vitamin D may be protective against breast cancer.
Dietary Fiber
Research suggests that some women who eat large amounts of fiber have
lower incidence of breast cancer. Insoluble fibers such as bran, obtained
from unprocessed grains, provide the most protection. Soluble fibers such
as apples, beans and oatmeal also appear to offer protection. The role
fiber plays in breast cancer prevention may stem from its ability to decrease
levels of circulating estrogens. High levels of estrogens may promote
the growth of breast tumors.
Diets high in fiber have also been linked to a lower incidence of heart
disease and possibly colon cancer. Studies show mixed results in relation
to colon cancer. The average American consumes about 14 grams of fiber
per day. For women aged 19 to 50 years, the recommended daily fiber intake
is 25 grams. For women over 50, the recommended daily fiber intake is
21 grams. Dietary fiber may be helpful in weight loss, as well, since
it promotes a feeling of satiety.
Caffeine
Caffeine is one of the most thoroughly investigated ingredients in the food supply, including its effects on women's health. Health concerns associated with caffeine include ulcers, fibrocystic breast disease, cardiovascular disease, heartburn, cancer and birth defects.
The body absorbs caffeine rapidly and, in turn, normally removes it 10 to 14 hours later. People differ greatly in their sensitivity to caffeine. Caffeine stimulates the brain, increases alertness, increases passage of food through the digestive system, increases stomach acid and heart rate, and relaxes certain muscles. Caffeine can relax the passageway that leads to the stomach and cause heartburn. The amount of caffeine consumed can influence whether or not any of these effects will occur.
Health concerns specific to women and caffeine include breast cancer, fibrocystic breast disease and osteoporosis. After careful review, there is not adequate evidence to link breast cancer with caffeine consumption.
An even more discussed concern over caffeine intake by women is the incidence of fibrocystic breast disease. Also known as benign breast disease, it is characterized by benign fibrous lumps and breast tenderness. It was once thought to be the result of caffeine in the diet. Some women report decreased tenderness with elimination of caffeine, but this is not universal. The largest study to date concluded that there is no evidence of a connection between fibrocystic breast disease and caffeine.
The case of caffeine and osteoporosis is more convincing. Caffeine is a diuretic, meaning it increases urine output. Therefore, with increased intake, we can lose more minerals like calcium in the urine. For women at risk for osteoporosis and postmenopausal women, this can pose a problem. It has been reported that postmenopausal women who drink just two cups of coffee per day have associated bone loss. However, this connection was made only with women taking less than 800 mg of calcium per day. If you drink caffeinated beverages, ensuring adequate calcium intake is important.
Nutrient Supplements
There are many vitamin and nutrient supplements on the market that manufacturers claim will enhance health and help reduce the effects of aging and degenerative diseases. Antioxidant vitamins, in particular, are receiving widespread attention. Evidence suggests that antioxidant vitamins C, E and beta-carotene (a precursor to vitamin A) may reduce the risk of some forms of cancer, heart disease, strokes and cataracts, as well as slow the aging process.
Antioxidants "mop up" free radicals that are produced by the body during normal cellular activity. Free radicals travel through the cell and change the structure, causing cellular damage. Such damage is believed to contribute to aging and various health problems.
Antioxidant vitamins are found in fruits and vegetables and in many other
foods. Women who eat large amounts of antioxidant- containing foods, such
as carrots and spinach, have demonstrated a decreased risk for heart attack
and stroke compared to women who eat few such foods. However, antioxidant
supplements have not been shown to provide the same benefits and are not
recommended to prevent CVD. Women at high risk for cardiovascular disease
may benefit the most from eating more antioxidant-rich fruits and vegetables.
Until further conclusive evidence is available, eating a balanced diet rich in antioxidant vitamins may be the best way to receive possible health benefits. Include antioxidant-rich foods in your diet, and remember to eat five servings of fruits and vegetables each day. This is an easy way to get your antioxidant nutrients naturally.
Eating fruits, vegetables and enriched whole grains and cereals also increases
folacin. Folacin or folate is important for preventing neural birth defects.
Women of child-bearing age should get 0.4 mg per day. Folate also lowers
homocysteine levels. High homocysteine levels increase risk of heart disease.
Like antioxidant supplements, folic acid supplementation (synthetic folate)
is not recommended to prevent CVD. Again, focus on incorporating more
fruits, vegetables and enrhiched whole grains and cereals into your diet.
| Table 2: Upping the antioxidant ante. |
| Vitamin |
Foods |
|---|
| Beta carotene |
Spinach, carrots, squash, broccoli, yams, tomatoes, cantaloupe, peaches, fortified grain products, kale, asparagus, pumpkins, apricots |
| Vitamin C |
Citrus fruit and juices (oranges and grapefruit), strawberries, kiwi, cantaloupe, green peppers, raw cabbage, spinach, kale, broccoli, collard greens, tomatoes, oranges |
| Vitamin E |
Vegetable oils, fortified cereals, dried apricots, meats |
| Source: Food Insight: Current Topics in Food Safety and Nutrition, International Food Information Council Foundation, Nov/Dec 1993. |
Summary
Nutrition can play a key role in health problems that are special to women. The Dietary Guidelines for Americans and the Food Guide Pyramid were created to help Americans plan dietary goals that promote health and prevent disease.
Women can use these tools to plan a diet that includes anti-oxidant-rich
fruits and vegetables, provides adequate fiber, is low in fat and dietary
cholesterol, and provides the needed calcium. Building a pyramid diet
each day is the easy way to practice good eating and help keep extra pounds
off your body as you age. See 9.306,
A Guide for Daily Food Choices.
References
- Asanovic, S., Nutrition Updates, Spring 1995, p.5.
- Caffeine and Health; Clarifying the Controversies. International Food
Information Council.
- Harvard Women's Health Watch. March 1995 , April 1995, May 1995.
- Women's Health Connection. Vol. I. Number 3, August/September 1993.
- Tufts University Health and Nutrition Letter. March 2002, December
2002, July 2006.
- American Heart Association. "Evidence-Based Guidelines for Cardiovascular
Disease Prevention in Women: 2007 Update." Circulation. 2007;115:1481-1501.
- Duyff, Roberta Larson. American Dietetic Association Complete Food
and Nutrition Guide, Revised and Updated 3rd Edition. New Jersey:
John Wiley and Sons, Inc, 2006.
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