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FFA
Issue 15, July 2002-Focus on Women's Health and Diet |
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t_Articles
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Focus on Women’s Health and Diet
From bonny baby to child, teenager and woman; through menarche,
child-bearing, breast-feeding and menopause - a woman goes through many
phases in one lifetime. Each phase is unique with slightly different
nutrient needs. Ongoing research is providing more information on the
changing nutritional needs. In this article AFIC highlights four nutrients
that may merit extra attention in women’s diets, helping women to sail
gracefully from childhood to womanhood and stay strong, hearty and happy
through the greying years.
Folate
Folate or folic acid, is a B vitamin that is especially important for women
throughout life. Beyond supporting growth and development, preventing birth
defects and anaemia, recent research is highlighting the importance of
folate in lowering risk of heart disease and certain cancers too.
Folate’s role in the formation of DNA (the genetic material in the nucleus)
makes it essential for periods of rapid growth and development viz., during
childhood, adolescence, and pregnancy. Folate deficiency in pregnancy has
been seen to cause neural tube defects, low birth weight babies and
premature deliveries. Since neural tube defects occur early in pregnancy,
even before most women know they are pregnant, and more than 50% of
pregnancies are unplanned, it is advisable for all women of child bearing
age to consider taking a folate supplement right up to the first trimester
of pregnancy. Folate is also essential for building fetal tissues and
organs. The baby takes what it needs from the mother’s stores; deficient
mothers may become naemic. Red blood cell development is dependent on folate
intake; a deficiency leads to a kind of anaemia in which red blood cells
cannot carry much oxygen.
Most women are at high risk of heart disease and the risk increases after
menopause. High blood homocysteine levels have been linked to increased risk
of heart disease. Folate, along with vitamins B6 and B12, is essential to a
process that clears homocysteine from the blood and may help lower the risk
of heart disease.
Low folate levels have also been implicated in the development of cervical,
colon and lung cancer. Researchers hypothesise that folate’s anti-cancer
role may be due to its ability to prevent a cancer-causing gene from being
switched on.
Calcium
Researchers estimate that by 2050, half of the world’s osteoporotic
fractures will occur in Asia (1). Osteoporosis is a debilitating
brittle-bone disease and can be prevented if women consume adequate calcium
and participate in regular weight-bearing exercise throughout life.
Calcium intake must especially be emphasized during the teen years. There
are 3 reasons for this: firstly, almost half of the adult skeleton is formed
during adolescence, secondly calcium absorption is very efficient during
this phase of life and thirdly it helps achieve peak bone mass potential.
The maximal bone density achieved is called peak bone mass and the more bone
a girl builds at this stage in life, the better off she will be as bone is
lost later in life (during menopause and aging) and osteoporosis becomes a
threat. During pregnancy and breast-feeding, additional calcium is needed
for the development of the baby’s bones; in case of a deficiency, the baby
draws on the mother’s bone calcium stores and weakens her bones. Another
advantage of adequate calcium in pregnancy, is reduced risk of high blood
pressure and toxemia.
During menopause, falling estrogen levels initiate bone loss. The earlier a
woman goes through menopause, the greater is this loss. A calcium-rich diet
or supplements along with weight bearing exercise and hormone replacement
therapy (HRT) slows bone loss to some extent during the peri-menopausal,
menopausal and post menopausal stages. For those with osteoporosis,
researchers have found that calcium intake helps enhance the efficacy of
osteoporosis medication.
Folate recommendation*
Adolescent girls and adult women 400mcg Pregnant women 600mcg Lactating
women 500mcg
Good Sources Green leafy vegetables; dried beans, peas and lentils;
orange juice, oranges and cantaloupes; fortified milk, ready-to-eat
fortified with folate, cereals and oats are good sources of folate. Many
other vegetables and fruits plus tea provide small amounts of folate.
Calcium recommendation*
Adolescent girls 12 - 18 years 1300mg Adult women (pre menopausal) 1000mg
Adult women (post menopausal) 1300mg Pregnant women 1200mg Lactating women
1000mg
Good Sources Dairy and soya milk and milk products such as cheese and
yogurt are excellent sources of well-absorbed calcium. Beancurd; green leafy
egetables; broccoli; and whole fish (sardines, salmon, ikan bilis) provide
some calcium too. For people who cannot consume enough calcium-rich foods,
calcium supplements are essential.
Phytoestrogen recommendation
The threshold intake of dietary phytoestrogens necessary to achieve a
biological effect in humans appears to be 30 to 50mg/day. (2)
Good Sources Phytoestrogens comprise isoflavones (particularly,
genistein and daidzein) found in soybeans, garbanzo beans, sprouting beans,
and other legumes; lignans found in seed oils, especially flaxseed. In Asia,
soy foods are the most popular source of phytoestrogens, the variety viz.,
tofu, tempeh, soy granules, soy sprouts, soy milk and soy flour and the
versatility of these foods makes them easy to include in the diet.
Nutritional iron recommendations
Teenage girls and Adult women 30mg/day Pregnant women - as above + 100
mg/day supplement Lactating women 15mg/day Post-menopausal women 11.3mg/day
Figures based on average 10% bio-availability of iron in diet
Good Sources Lean red meat, chicken, pork and fish are all good sources
of Iron-fortified breakfast cereals, eggs, legumes, dark green vegetables
also provide some iron, but this is less well absorbed by the body than meat
and fish sources. The iron in plant-based foods is better absorbed if eaten
with meat and fish iron containing foods. Vitamin C found in citrus fruits
and juices also improve uptake of iron by the body.
Phytoestrogens
Phytoestrogens are weak plant estrogens that are similar in structure and
have the ability to mimic the action of the female hormone estrogen.
Researchers believe that a phytoestrogen-rich diet can help curb symptoms of
menopause, prevent bone disease, promote cardiovascular wellness and lower
risk of certain cancers.
Menopause occurs as the ovaries produce less estrogen. It is believed that
during menopause, phytoestrogens fill up empty estrogen receptor sites and
exhibit a weak (1/100th to 1/1000th strength of estradiol) pro-estrogenic
effect. A higher intake of food-based phytroestrogens is probably the reason
why many Asian and Oriental women have an easier time and experience less
hot flushes during menopause than women in western society. The traditional
Japanese diet for exmaple, contains 30-100 times more phytroestrogens than a
typical western diet. Phytoestrogen-rich diets have also been linked to an
increase in bone mineral content in postmenopausal women. In fact,
phytoestrogen supplementation is being considered a potential alternative or
complement to conventional hormonal replacement therapy for osteoporosis
prevention.
Coronary Heart Disease (CHD) is the major cause of morbidity and mortality
in women. The incidence of CHD in premenopausal women is low, but it
increases dramatically after menopause. This difference suggests that
endogenous estrogens are cardioprotective. Since some women may not be able
to take hormones, researchers are looking at foods that have estrogen like
compounds in them. Studies on the soy isoflavones - phytoestrogens in soy
and its impact on CHD have determined that phytoestrogens have the ability
to slow the development of atherosclerotic diseases; lower lipid levels and
inhibit low-density lipoprotein oxidation.
Maintaining a hormonal balance is a key factor in preventing and reversing
hormone sensitive cancers. Researchers believe that phytoestrogens lower
risk of breast, endometrial and ovarian cancers by acting as estrogen police
and maintaining estrogen levels in the body.
While research on phytoestrogens is not conclusive and more studies on women
using phytoestrogens need to be done to establish both benefits and risks,
use of naturally occurring phytoestrogens in food can be considered a
relatively safe method of affecting estrogen activity.
Iron
Iron is an essential mineral found. Much of the body’s iron is found in red
blood cells, where it plays a key role in carrying oxygen around the body.
The body does store some iron in the liver, but reserves are limited, so
regular consumption of good dietary sources are essential. Women are
especially prone to iron-deficiency, because of menstrual blood loss.
Pregnancy brings additional dietary iron demands because of increased blood
volume requirements for both mother and developing foetus and the blood loss
associated with childbirth. The 1998 WHO/FAO Expert Consultation concluded
that it would be very difficult for pregnant women to meet all their
increased iron needs from diet alone, and therefore recommend routine iron
supplements. Some teenage girls are also at high risk of iron deficiency
because of a combination of dietary restrictions such as low calorie or
avoidance of animal product, menstrual blood loss, and increased need for
dietary iron during growth spurts. In fact, hundreds of years ago, doctors
believed that the symptoms of iron deficiency anemia (paleness of skin,
lethargy) were associated with being in love because it was recognized that
mainly young women suffered from the condition.
Signs of possible iron deficiency are irritability, difficulties in
concentration, tiredness, plus increased susceptibility to infections.
Physical body signs to look out for include paling of skin colour, eye
membranes and nailbeds, and slow wound healing. Chronic deficiency can
result in depletion of body iron stores resulting in anaemia with loss of
appetite, extreme fatigue and an inability to regulate body temperature
efficiently. Those who suspect they may be lacking in iron should see their
doctor for a simple blood test. For those who cannot consume enough iron
from dietary sources because of poor appetite or increased needs, an iron
supplements may be advised.
(1)
http://www.inq7.net/lif/2001/oct/20/lif_5-1.htm * Based on the joint WHO/FAO
provisional recommendations 1999
(2) Setchell KD. Phytoestrogens: the biochemistry, physiology, and
implications for human health of soy isoflavones. Am J Clin Nutr 1998 Dec;68
(6Suppl): 1339S-1346S. |
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