Whoever said that “you are what you eat” was not wrong. The composition of our diets can affect everything from our moods to our risk of getting some types of cancer.
Now it looks as if nutrition may also be an essential part of helping at least one type of infertility.
There are literally hundreds of causes of infertility, but one of the more common ones in women is a problem with ovulation. A rapidly growing cause of ovulatory problems is the polycystic ovarian syndrome, which is itself associated with insulin resistance.
New research from Harvard School of Public Health is published today in the prestigious journal Obstetrics & Gynecology which suggests that women who followed a combination of five or more lifestyle factors, including changing specific aspects of their diets, had more than 80 percent less relative risk of infertility due to ovulatory disorders when compared with women on more unhealthy diets.
The investigators followed a group of 17,544 married women who were participating in the Nurses' Health Study II, which is based at the Brigham and Women's Hospital in Boston. The researchers created a scoring system on dietary and lifestyle factors that previous studies have found to predict ovulatory disorder infertility. Among those factors were:
- The ratio of mono-unsaturated to trans fats in diet
- Consumption of animal or vegetable protein consumption
- Carbohydrates consumption, which included both dietary fiber the glycemic index of foods
- Dairy consumption: both low- and high-fat
- Iron consumption
- Multivitamin use
- Body mass index
- Level of physical activity
The researchers then assigned a "fertility diet" score of one to five points. The higher the score, the lower the risk of infertility associated with ovulatory disorders.
The women with the highest fertility diet scores ate:
- Less trans fat
- Less sugar from simple carbohydrates
- More vegetable than animal protein
- More fiber and iron
- More multivitamins
- More high-fat dairy products and less low-fat dairy products
The more fertile women also had a lower BMI and exercised for longer periods of time each day.
This relationship between a higher "fertility diet" score and lesser risk for infertility was similar for different subgroups of women. It seemed to hold in many different age groups, and whether or not a woman had been pregnant in the past.
The effect size is impressive: women following five or more low-risk dietary and lifestyle habits have a six fold reduction in ovulatory infertility risk compared with women following none of them.
There are two surprises here. It has been believed that heavier – though not obese – women tended to be more fertile. That is not what this study found. Second, the higher fertility rates of women who consume high-fat dairy products and less low-fat dairy products may seem counter-intuitive. But well-nourished women would be expected to have a higher chance of being fertile.
The take home message is this: if a woman is having problems with ovulation, sensible dietary choices and a moderate amount of physical activity may make a large difference in her chance of becoming fertile.
This all makes sense. From an evolutionary perspective it could be dangerous to bear a child while ingesting foods, chemical or toxins that could harm a baby, or could compromise the health of a pregnant mother.
"Nutrition can be compared with a chain in which all essential items are separate links. We know what happens if one link of a chain is weak or is missing. The whole chain falls apart.”
--Patrick Wright (American Director of the Institute for Research on Food-related Disease)
“Health requires healthy food.”
--Roger Williams (Indian-born American Chemist who did pioneering work on the Vitamin B Complex, 1893-1988)