| ||Food for Thought || |
Can Your Diet Affect Fertility?
May 4, 2012
By Brianna Gray, M.S.
Brigham and Women's Hospital
About one in six couples in the United States experience infertility. Assisted reproductive technologies (ART) are methods couples use to help couples have children.
Both the success rates and the number of people who use ART, such as in vitro fertilization, have grown over the past few decades. However, these methods do not guarantee pregnancy. Although lifestyle changes, such as following a healthy diet, may not replace fertility treatments, they can significantly improve both your health and your fertility.
Even if you are not experiencing fertility problems, boosting your health before pregnancy will make it easier for you to conceive, reduce pregnancy complications and improve your baby's health. The following recommendations can help increase your chances of conceiving.
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Maintain (or Work Towards) a Healthy Weight
Research has found that women with body mass indexes (BMI) between 20 and 24 (21 is optimal) have the best chance of getting pregnant. Women with BMIs outside that range have more difficulty conceiving. (Calculate your BMI here.
Daily exercise increases your energy and helps you shed unwanted pounds. It also improves blood sugar control, insulin sensitivity and fertility.
Staying active throughout your pregnancy will enhance your mood and energy level, reduce physical discomfort and make for an easier labor.
- A mixture of strength training, cardio and stretching will help you reap the most benefits.
- Find a variety of activities you enjoy and mix it up to avoid boredom.
- Aim for 30 to 60 minutes most days of the week.
Keep in mind, more is not necessarily better. If you are very lean, too much exercise could actually increase your risk of infertility.
Remember to consult your doctor before starting an exercise program.
Being underweight or overweight can alter the body's hormonal cycles and interfere with ovulation. Excess weight is also associated with insulin resistance and can lower the success rate of ART. Men should also be mindful of their weight. Being overweight lowers testosterone and sperm production.
The good news? If you are underweight, gaining just 5 to 10 pounds could help restart ovulation and improve fertility. If you are overweight, losing just 5% to 10% of your body weight significantly improves fertility, even if you are well above the ideal body weight range.
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Choose the Right Carbohydrates
Diets like Atkins, South Beach and Dukan have given carbohydrates a bad rap. But for overall health and to improve fertility, it's important to include high-quality carbohydrates in your diet every day.
Low glycemic index (GI) carbohydrates (whole grains, beans and legumes, and fruits and vegetables) stabilize blood sugar and insulin. They are better for fertility than high GI carbohydrates (white bread, pasta or rice, soda, fruit juice and candy). It's unknown exactly how elevated blood sugar and insulin resistance contribute to infertility. But studies have found a link between diets high in low GI carbohydrates and ovulatory fertility.
Women with polycystic ovary syndrome (PCOS), a disorder characterized by poor insulin sensitivity and infertility, have improved fertility rates following treatment with insulin-sensitizing drugs. In addition to keeping blood sugar steady, low GI carbohydrates also have more fiber, vitamins, minerals and protein than their refined counterparts.
- Choose a piece of fruit instead of fruit juice.
- Select whole grain pasta and brown rice instead of white.
- Balance your meals and snacks by including protein and healthy fats with your low GI carbohydrates for an even better blood sugar response.
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Pick Plant Proteins
Research has found that replacing animal proteins with plant proteins reduces the risk of infertility by 50%. For a fertility boost, aim for at least half of your protein to come from nuts and nut butters, beans and legumes, edemame, tofu and eggs.
- Add nuts to salads, cereal or baked goods.
- Instead of chicken on your salad, try black beans or grilled tofu.
- Pack healthy snacks: crackers with nut butter, edamame or hummus with veggies.
- Get creative! Experiment with vegetarian versions of your favorite recipes.
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Including healthy fats in your diet, and avoiding the unhealthy ones, is an important step to improved fertility. Unhealthy trans fats (hydrogenated oils found in many baked goods, crackers and cookies) promote inflammation and insulin resistance.
Inflammation can reduce the body's sensitivity to insulin by blocking key proteins, such as adiponectin and PPAR-gamma, involved in insulin-sensitivity. Also, insulin resistance has been associated with infertility. Mono- and polyunsaturated fats have the opposite effect they reduce inflammation and are good for fertility. Replacing trans fats with mono- and polyunsaturated fats is a great way to improve your fertility and overall health.
- Cook with olive or canola oil instead of margarine, shortening or butter.
- Read food labels. Avoid foods that contain trans fats or have "partially hydrogenated" oils in the ingredient list.
- Include healthy fats, such as avocados, nut butters, olives and olive oil, with your meals daily.
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Skip the Skim
This is one case when whole milk gets the thumbs up. Research has found that women who drank one serving of whole milk a day had an easier time getting pregnant that those who did not drink milk or who ate low-fat dairy foods.
Whole milk contains fat-soluble hormones that appear to be important for fertility. These hormones are lost during the skimming process. Thus, whole milk's better hormonal mix may explain the improvement in fertility among women who drank it compared with those who drank 1% or skim.
- Drink whole milk instead of skim, but don't go crazy. Whole milk has almost double the calories. Women can reap the benefits of full-fat dairy (and minimize the drawbacks) with only one serving of whole milk per day.
- Enjoy ½ cup of ice cream a few times a week instead of low-fat frozen yogurt.
- Cutting back on red meat will help balance out whole milk's added calories and saturated fat, and also improve fertility.
Full-fat dairy products may improve fertility, but don't overdo it. Remember, maintaining a healthy weight is an important piece of the fertility puzzle. Once you are pregnant, it's a good idea to drink heart-healthy skim or 1% milk again.
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Take a Multivitamin
Conception requires extra folic acid and iron. Folic acid is essential during the early prenatal period to prevent neural tube defects birth defects of the brain and spinal cord. Taking a prenatal vitamin is associated with improved fertility in women. And daily multivitamin/mineral supplements improve sperm counts in men.
Women who are planning a pregnancy should take a prenatal vitamin that contains nonheme iron (from plant sources) as this appears to help fertility more than heme iron. Men who are looking to boost their fertility do best sticking with a standard multivitamin/mineral supplement.
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The Bottom Line
Simple, inexpensive changes to your diet and lifestyle could greatly improve your chances of getting pregnant and having a healthy pregnancy. So:
- Maintain a healthy weight.
- Stay physically active.
- Choose a well-balanced diet that is mostly based on low GI carbohydrates, plant-based proteins and healthy fats.
- Take a daily multivitamin if you are a man or a prenatal vitamin if you are a woman to help ensure that you are consuming enough of all the micronutrients needed for conception and a healthy pregnancy.
CDC. Fertility, Family Planning, and Reproductive Health of U.S.Women: Data From the 2002 National Survey of Family Growth Series 23, No. 25, Table 69. Dec 2005. Retrieved from: http://www.cdc.gov/nchs/data/series/sr_23/sr23_025.pdf.
CDC. ART National Summary Report. January 2011. Retrieved from: http://apps.nccd.cdc.gov/art/Apps/NationalSummaryReport.aspx.
Rich-Edwards JW, Spiegelman D, Garland M, Hertzmark E, Hunter DJ, Colditz GA, et al. Physical activity, body mass index, and ovulatory disorder infertility. Epidemiology. 2002; 13:184-190.
Chavarro J, Willett WC, Skerrett PJ. The Fertility Diet. McGraw-Hill, 2007.
Chavarro JE, Rich-Edwards JW, Rosner BA, Willett WC. A prospective study of dietary carbohydrate quantity and quality in relation to risk of ovulatory infertility. European Journal of Clinical Nutrition. 2009 Jan; 63(1):78-86. Epub 2007 Sep 19.
Redfern J. Combating Polycystic Ovary Disease Through Diet. August 10, 2010. Retreived from: http://www.intelihealth.com/IH/ihtIH/WSIHW000/35320/35327/366809.html?d=dmtHMSContent.
Nestler JE, Stovall D, Akhter N, Iuorno MJ, Jakubowicz DJ. Strategies for the use of insulin-sensitizing drugs to treat infertility in women with polycystic ovary syndrome. Fertility and Sterility. 2002; 77:209-215.
Gregor MF, and Hotamisligil GS. Inflammatory mechanisms in obesity. Annual Review of Immunology. 2011; 29:415-445.
Chavarro JE, Rich-Edwards JW, Rosner B and Willett WC. A prospective study of dairy foods intake and anovulatory infertility. Human Reproduction. 2007; 22:1340-1347.
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Brianna Gray, M.S., is a dietetic intern at Brigham and Women's Hospital.