http://www.newsweek.com/id/73354
Fat, Carbs and the Science of Conception
*CARBS*
In a nutshell, results from the Nurses' Health Study indicate that the amount of carbohydrates in the diet doesn't affect fertility, but the quality of those carbohydrates does. Eating a lot of rapidly digested carbohydrates that continually boost your blood-sugar and insulin levels higher can lower your chances of getting pregnant. This is especially true if you are eating carbohydrates in place of healthful unsaturated fats. On the other hand, eating whole grains, beans, vegetables and whole fruits—all of which are good sources of slowly digested carbohydrates—can improve ovulation and your chances of getting pregnant.
*FATS*
Trans fats were a different story. Across the board, the more trans fat in the diet, the greater the likelihood of developing ovulatory infertility. We saw an effect even at daily trans fat intakes of about four grams a day. That's less than the amount the average American gets each day.
Eating more trans fat usually means eating less of another type of fat or carbohydrates. Computer models of the nurses' diet patterns indicated that eating a modest amount of trans fat (2 percent of calories) in place of other, more healthful nutrients like polyunsaturated fat, monounsaturated fat or carbohydrate would dramatically increase the risk of infertility. To put this into perspective, for someone who eats 2,000 calories a day, 2 percent of calories translates into about four grams of trans fat. That's the amount in two tablespoons of stick margarine, one medium order of fast-food french fries or one doughnut.
Fats aren't merely inert carriers of calories or building blocks for hormones or cellular machinery. They sometimes have powerful biological effects, such as turning genes on or off, revving up or calming inflammation and influencing cell function. Unsaturated fats do things to improve fertility—increase insulin sensitivity and cool inflammation—that are the opposite of what trans fats do. That is probably why the largest decline in fertility among the nurses was seen when trans fats were eaten instead of monounsaturated fats.
*PROTEIN*
When we looked at animal protein intake separately from plant protein, an interesting distinction appeared. Ovulatory infertility was 39 percent more likely in women with the highest intake of animal protein than in those with the lowest. The reverse was true for women with the highest intake of plant protein, who were substantially less likely to have had ovulatory infertility than women with the lowest plant protein intake.
That's the big picture. Computer models helped refine these relationships and put them in perspective. When total calories were kept constant, adding one serving a day of red meat, chicken or turkey predicted nearly a one-third increase in the risk of ovulatory infertility. And while adding one serving a day of fish or eggs didn't influence ovulatory infertility, adding one serving a day of beans, peas, tofu or soybeans, peanuts or other nuts predicted modest protection against ovulatory infertility.
(SO much more at link)
Fat, Carbs and the Science of Conception
*CARBS*
In a nutshell, results from the Nurses' Health Study indicate that the amount of carbohydrates in the diet doesn't affect fertility, but the quality of those carbohydrates does. Eating a lot of rapidly digested carbohydrates that continually boost your blood-sugar and insulin levels higher can lower your chances of getting pregnant. This is especially true if you are eating carbohydrates in place of healthful unsaturated fats. On the other hand, eating whole grains, beans, vegetables and whole fruits—all of which are good sources of slowly digested carbohydrates—can improve ovulation and your chances of getting pregnant.
*FATS*
Trans fats were a different story. Across the board, the more trans fat in the diet, the greater the likelihood of developing ovulatory infertility. We saw an effect even at daily trans fat intakes of about four grams a day. That's less than the amount the average American gets each day.
Eating more trans fat usually means eating less of another type of fat or carbohydrates. Computer models of the nurses' diet patterns indicated that eating a modest amount of trans fat (2 percent of calories) in place of other, more healthful nutrients like polyunsaturated fat, monounsaturated fat or carbohydrate would dramatically increase the risk of infertility. To put this into perspective, for someone who eats 2,000 calories a day, 2 percent of calories translates into about four grams of trans fat. That's the amount in two tablespoons of stick margarine, one medium order of fast-food french fries or one doughnut.
Fats aren't merely inert carriers of calories or building blocks for hormones or cellular machinery. They sometimes have powerful biological effects, such as turning genes on or off, revving up or calming inflammation and influencing cell function. Unsaturated fats do things to improve fertility—increase insulin sensitivity and cool inflammation—that are the opposite of what trans fats do. That is probably why the largest decline in fertility among the nurses was seen when trans fats were eaten instead of monounsaturated fats.
*PROTEIN*
When we looked at animal protein intake separately from plant protein, an interesting distinction appeared. Ovulatory infertility was 39 percent more likely in women with the highest intake of animal protein than in those with the lowest. The reverse was true for women with the highest intake of plant protein, who were substantially less likely to have had ovulatory infertility than women with the lowest plant protein intake.
That's the big picture. Computer models helped refine these relationships and put them in perspective. When total calories were kept constant, adding one serving a day of red meat, chicken or turkey predicted nearly a one-third increase in the risk of ovulatory infertility. And while adding one serving a day of fish or eggs didn't influence ovulatory infertility, adding one serving a day of beans, peas, tofu or soybeans, peanuts or other nuts predicted modest protection against ovulatory infertility.
(SO much more at link)
