The Fertility Diet
It is well established that diet, exercise, and body weight affect your
fertility. The general rule of "all things in moderation" will serve
your well! If your weight is too high or too low, your ovulation will be affected.
If you exercise too much or too little your ovulatory function will be similarly
affected. As far as diet is concerned, recent research from the Nurses' Health Study
offers some important insights. Drs. Chavarro and Willett in their recent book
"The Fertility Diet" analyzed data from 18,000 women followed in the Nurses'
Health Study. They looked at dietary and other factors in terms of their effects on
fertility. After 8 years of follow up one in six women had difficulty conceiving.
They found that diet can affect the risk of ovulatory infertility.
There is no information here for men since only women were included in the study.
It is also important to know that no other cause of infertility such as tubal
blockage was correlated with diet. Other studies back this up. The only clear
link between diet and fertility appears to be related to ovulatory function.
Ovulation problems are a common cause of infertility being a factor in at least 30% of
cases. How do you know if your ovulation is a problem? The 2 most common
signs are irregular menstrual cycles or abnormal body weight.
What is an abnormal menstrual cycle? Your cycle
length is the time from your first day of full flow one cycle to the first day of the next
cycle. If your cycle length is less than 25 or more than 32 days it may be a
problem. Your doctor can do specific testing such as blood work or ultrasound to
confirm an ovulation problem.
What is abnormal body weight? Many tables of body
weight are available. A good general rule for women is to allow 100 pounds for the
first 5 feet of height and then 5 additional pounds for each inch. If you are 5'6''
tall and of medium frame the formula would yield an ideal body weight of 130 pounds.
Allow 10% less for small frame and 10% more if you have a large frame. If
your weight is too much above or too much below the ideal your ovulation could be
affected.
The Fertility Diet
Low carb / Slow carb
Carbohydrates are our source of quick energy. They are rapidly
metabolized into sugars which can be used to fuel our immediate energy needs such as in an
exercise state or be immediately stored in the form of fats. Unfortunately the last
decade can be described as the low fat decade. We were all told that fats are bad
for us. Reducing fat intake meant increasing carbohydrate intake for most of us.
Unfortunately it is much easier to gain weight from carbs than from fat. It
is simply much easier to intake a large amount of calories in the form of carbohydrates.
It turns out that not all carbs are created equal. Fast carbs have a high
glycemic index and are rapidly metabolized into sugars which cause weight gain and insulin
resistance which in turn disturbs normal ovulation. Examples of fast carbs are white
rice, white bread, potatoes, cookies, ice cream and sodas. Slow carbs are better for
fertility and include brown rice, whole grain pasta and dark bread. Whole grains,
vegetables and whole fruit all contain slow carbs.
Good fats and bad fats
Some fats are healthy for you and needed by your body. These are
called essential fatty acids. Many prenatal vitamins are fortified with essential
fatty acids. Natural foods containing these fats include fish and fish oils and some
nuts.
Most fats found in our food can be divided based on their chemical
structure as saturated and unsaturated. During the past decade we were told that
using a lot of saturated fats like butter was not good for your heart. Recently we
discovered that a type of unsaturated fat is also not good for you. This type of fat
is called a trans fat. These fats are manufactured by a process of hydrogenation of
oils to create a product which when used in cooking results in a high shelf like for
foods. Trans fats are bad for your heart and your fertility. The FDA now
requires food labeling which details the amount of trans fats. Some cities such as
New York have banned the use of trans fats from all their restaurants. Be careful
with the following foods which can be high in trans fats: French fries, stick
margarines, shortening, potato chips, doughnuts and cake.
The following tips are from the FDA:
Here are some practical tips you can use every day to keep your consumption of
saturated fat, trans fat, and cholesterol low while consuming a nutritionally
adequate diet.
- Check the Nutrition Facts panel to compare foods because the serving sizes are generally
consistent in similar types of foods. Choose foods lower in saturated fat, trans
fat, and cholesterol. For saturated fat and cholesterol, keep in mind that 5 percent of
the Daily Value (%DV) or less is low and 20 percent or more is high. (There is no %DV for trans
fat.)
- Choose alternative fats. Replace saturated and trans fats in your diet with
monounsaturated and polyunsaturated fats. These fats do not raise LDL cholesterol levels
and have health benefits when eaten in moderation. Sources of monounsaturated fats include
olive and canola oils.Sources of polyunsaturated fats include soybean oil, corn oil,
sunflower oil and foods like nuts.
- Choose vegetable oils (except coconut and palm kernel oils) and soft margarines (liquid,
tub, or spray) more often because the combined amount of saturated fat and trans
fat is lower than the amount in solid shortenings, hard margarines, and animal fats,
including butter.
- Consider fish. Most fish are lower in saturated fat than meat. Some fish, such as
mackerel, sardines, and salmon, contain omega-3 fatty acids, which are being studied to
determine if they offer protection against heart disease. Some large fish which live
for long periods of time can accumulate mercury. It is therefore suggested that
pregnant women limit the intake of such large fish such as Shark, Sword fish, and Albacore
tuna to two servings per week. Smaller fish such as Salmon or Tilapia is not a
concern. They do not live long enough to accumulate significant quantities of
mercury.
- Choose lean meats, such as poultry without the skin and not fried and lean beef and
pork, not fried, with visible fat trimmed.
- Ask before you order when eating out. A good tip to remember is to ask which fats are
being used in the preparation of your food when eating or ordering out.
- Limit foods high in cholesterol such as liver and other organ meats, egg yolks, and
full-fat dairy products, like whole milk.
- Choose foods low in saturated fat such as fat free or 1% dairy products, lean meats,
fish, skinless poultry, whole grain foods, and fruits and vegetables.
Proteins
Proteins are what's for dinner. These include the well known animal proteins such
as beef, pork, chicken and fish. In general these are an important part of your diet
and will lead to less weight gain than fats and carbohydrates. Less well known are
vegetable proteins which appear to be better for your fertility. These include
beans, peas and tofu (soy bean derivative). Peanuts and other nuts are also a good
source of vegetable proteins. More protein intake particularly from a vegetable
source can improve fertility.
Milk
Milk has been a source of controversy with some studies showing that it helps fertility
and other studies showing a harmful effect. The most recent study show that two
servings per day of whole milk or products of whole milk are beneficial. That could
be in the form of a glass of milk and a cup of yogurt. In this study whole was
better than skim. If your weight is increased, you may need to substitute skim milk
since the effect of the weight is itself significant and unfortunately milk is rich in
calories.
Body Weight
There is no question that weight is a major factor affecting fertility. Most
commonly this is high body weight but in some cases low body weight can be a problem.
There are many diets which can be of help. These range from Atkins high
protein diet to weight watchers or Jenny Craig. It is important to find some system
that you believe in and to set modest goals such as a 10% initial weight loss.
Remember that the first week of any dietary change is the hardest. After the first
week you will be more acclimated to this change and progress can begin. Too many
carbs are frequently the problem with the modern convenience food diet. Remember it
is easier to gain weight from too many carbs than any other single category.
Exercise
Exercise was also shown to boost fertility. A reasonable plan is to set aside 30
minutes every day for exercise. This can be aerobic such as walking fast or running
or muscle building such as working with weights. A mixture of both forms is probably
the best. Anything is probably better than nothing. Remember that the longest
journey begins with one step. Exercise has many other benefits such as improving
heart health and longevity.
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