 Harvard study proves a healthy diet can overcome infertility
Infertility affects one couple in six, but simple lifestyle measures can help many couples conceive, say US researchers. source: ABC Health and Wellbeing Australia Date: 11/8/07
In our parents' day most women were married and had at least one kid by the age of 25. That seems like a lifetime ago.
These
days in Australia most women give birth in their 30s. While they may be
in a better position financially and perhaps mentally – in a more
stable relationship, with a higher income – they're much less likely at
that age to actually fall pregnant.
Women are most fertile between 17 and 25. Over the age of 35, one woman in three will have trouble getting pregnant.
It's
not always the woman's fault – in 40 per cent of cases the finger can
be pointed at the male. (In 40 per cent of cases the problem lies with
the woman; in 10 per cent there is a problem with both partners and in
another 10 per cent, the cause is unknown.)
There are various
reason why a woman finds it harder to conceive in these later years –
there may be a structural problem with the reproductive organs, like
blocked fallopian tubes, or a disease of the uterus like fibroids or
endometriosis.
Most cases, though, are due to a failure of
ovulation – eggs just don't ripen and release when they're supposed to.
This is usually because of a hormonal imbalance – at an older age, the
body isn't producing enough sex hormones at the right time and in the
right amounts to ovulate successfully.
For these women, IVF (In
Vitro Fertilisation) is an option, but it's not the preferred one:
apart from anything else, it's time consuming, expensive and has a high
failure rate.
But there's some good news this month from the US.
Researchers from the Harvard School of Public Health and Harvard
Medical School say that adopting a few lifestyle measures can
drastically improve the chances of getting pregnant, at any age.
They
followed a group of 17,544 married women who were infertile due to
ovulation failure but who were trying to get pregnant. The women were
part of a larger study of women's health called the Nurses' Health
Study II, based at the Brigham and Women's Hospital at Harvard. The
researchers followed them over an eight-year period, looking in
particular whether or not they followed a range of dietary and
lifestyle measures. They looked at:
- the ratio of mono-unsaturated to trans fats in their diet
- protein consumption (and whether it came from animals or vegetables)
- carbohydrate consumption (including the amount of fibre they ate, and whether high or low glycaemic index)
- consumption of dairy products (and whether low or high-fat)
- iron consumption
- use of vitamin supplements
- body mass index (BMI, i.e. weight in kilograms divided by the square of the height in metres) and
- degree of physical activity.
The
researchers took into account whether a woman smoked, drank alcohol or
coffee, and/or had used oral contraceptives in the past.
Those
women with the lowest rate of infertility (and most likely to fall
pregnant) were those who ate less trans fat, less sugar, ate food with
a low glycaemic index such as pasta and whole grains, ate more protein
from vegetables than from animals, had a good iron intake, took
multivitamins, exercised daily, kept their BMI between 20 and 25, and
(surprisingly) consumed more high-fat dairy products and less low-fat
dairy products.
The more of these measures they adopted, the
lower the infertility rate and the higher the pregnancy rate. This was
regardless of the woman's age, or whether she'd had children before.
For
example, those who adopted just five of these measures had a 69 per
cent reduced risk of infertility compared to those who adopted none of
the measures.
Even following just one of these lifestyle measures
reduced the risk of infertility by 30 per cent compared to those women
who followed none. Of all the lifestyle measures, weight and diet,
rather than exercise, were the most important.
Blood sugar and insulinWhy
should these measures improve fertility? It's believed they improve
insulin resistance – that is, they help regulate insulin and blood
sugar levels and this in turn may help the sex hormones to regulate
ovulation successfully.
Why high fat dairy products help remains a mystery though. Now
adopting these measures won't necessarily work for other types of
infertility, such as blocked fallopian tubes. But what it does mean is
fertility due to ovulation problems – which account for most
infertility cases – can be partly prevented through modifications of
diet and lifestyle, the authors say.
As an added bonus, these
measures are also good for the pregnancy if a woman does conceive, they
say. Taking multivitamins containing folic acid helps prevent neural
tube defects in the foetus. And keeping weight down reduces the chances
of pregnancy complications like gestational diabetes or pre-eclampsia.
Not to mention avoiding having to explain, when the boy or girl gets a bit older, how some babies come from test tubes.
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