Personalized Nutrition for Optimum Fertility – A guest post by Gil Wilshire, MD
Nutrition-related diseases are common in our fertility practice. Patients with these issues are actually experiencing sub-fertility, however, and they generally have excellent fertility potential. Evidence- and experience-based recommendations are improving and we now have a growing experience of effective treatments. In addition, we may expect very exciting new research results in the next few years with regard to the role of gut flora and obesity, for example. Researchers are very close to proving we are not what we eat, but what we absorb. This is an exciting and evolving field and numerous advances can be expected in the coming years. Carbohydrate restriction has become a first-line, mainstream treatment in many fertility and medical clinics. Resistance to these measures appears to be waning as the benefits of these interventions become more and more obvious.
Nutrition is the cornerstone of human health. Few subjects are more important with regard to the prevention and treatment of human disease; including sub-fertility. As the practice of medicine becomes more evidence-based, the need for good data continues to grow. The field of nutrition is very different from others, however, and its unique challenges have severely hindered progress in this clinical area.
The Problem with Nutritional Science
The field of nutritional science suffers from numerous problems. We simply don’t have good data to make scientific recommendations in many cases. This is the reason nutrition lags behind other clinical sciences. One huge problem is due to our inability to do “double-blinded” food studies. You cannot hide food from people as they eat it! When subjects and researchers know what they are eating, biases can affect outcomes. It is also very hard to control what people eat when they are living in the real world. Unless one puts subjects on a “metabolic ward” (that is in lockdown!) one can never be sure that someone isn’t cheating on their diet. Another problem relates to the concept of context. Sometimes something is good, yet at another time, it can be bad! For example, if you are dying of thirst, water is life-saving. Yet too much water can drown you! Saturated fat may be good for you in the context of a low-carb diet, but add white potato fries, and you may have a problem. Determining optimum levels of nutrients is also very difficult. We are a versatile and resilient species, and we can adapt to broad ranges of diets. Finding (or proving) the optimal “sweet spot” for a nutrient is virtually impossible. People are also genetically diverse. What is good for one person may not be so good for another. One size does not fit all!
What is Known
Extremes of body size and energy intake have well-established effects on fertility. Underweight or malnourished women clearly have impaired fertility. It has been known for centuries that obesity can be a problem as well. It is reasonable to assume that micronutrient deficiencies (like vitamins and minerals) likely play a role, too. In real life, nutritional deficiencies and other fertility-altering behaviors are not always obvious. Obesity and very low body fat are generally easier to pick up. The most common measurement for being too fat or too skinny is the body mass index (BMI, kg/m^2). The optimum BMI for fertility is probably somewhere around 22-23. It is fairly clear that a BMI less than 19 or greater than 28 can cause problems (both in conceiving a pregnancy and in carrying it).
Malabsorption SyndromesMalabsorption is an occasional cause of nutritional deficiency and ill health, including fertility problems. Diarrhea, weight loss, and fatigue are the most common symptoms. These issues may be chronic, and may be regarded as “normal” if someone doesn’t know any better. People frequently compensate for their issues by taking over the counter medications and by avoiding bothersome foods. Digestion problems can also be caused by non-medical issues. “Irritable bowel syndrome” (IBS) may be normal bowel reactions to highly stressful life situations. Abusive relationships, stressful work environments, and the stress of infertility can all cause reactive bowel issues. Another cause of diarrhea is endometriosis. Careful evaluation of the timing of the bowel symptoms with regard to the menstrual cycle is crucial. Women are frequently bounced between family doctors, internists, gastroenterologists and psychiatrists before being properly evaluated by a fertility specialist. Endometriosis is frequently found in these women (even with a normal pelvic exam and sonogram) and aggressive surgical treatment by a very experienced surgeon frequently delivers gratifying results. A knowledgeable gastroenterologist (GE) is sometimes a key player in sorting out malabsorption issues. A GE who has the patience and sensitivity to interact with “high maintenance” fertility patients is a valuable resource and is not easy to find in my experience.
Underweight and Eating Disorders
Treatment of the underweight woman – particularly the adolescent – is very challenging. A BMI less than 19 is a strong clue that there is a problem. Muscular athletic women may have very low body fat but a normal BMI; this, too, can be a problem. A total body fat of 22-25 percent may be optimal for fertility and successful pregnancy. This is a hard pill to swallow for many women.
Young women with eating disorders are very difficult to treat. Initial success revolves around finding almost anything that a woman will eat! Migration to wholesome, nutrient-dense eating patterns comes later. Counselors with experience dealing with eating disorders and body image issues are valuable in these situations.
Polycystic Ovarian Syndrome (PCOS)
Few conditions in endocrinology and infertility are as misunderstood as PCOS. The mistake that pervades the subject is that PCOS is some type of disease. It is NOT! PCOS is a spectrum of conditions that are, in fact, beneficial and adaptive to survivial and reproduction in various environmental situations. The genetics of PCOS have been with us for thousands of years, and if the conditions truly caused infertility, the genes would have died off a long time ago. If one is able to reproduce the social and dietary context in which PCOS is beneficial, then one can effectively treat the condition.
As stated above, PCOS is a spectrum of conditions. For the sake of discussion, however, the condition can be divided into two basic groups.
Lean PCOSLean PCOS accounts for about 15 – 20 percent of PCOS patients. Other descriptive names include “athletic” or “hunter” PCOS. These women are frequently athletes from their early teen years. In fact, a large number of olympic female athletes appear to have this condition! Lean PCOS women tend to have bad facial acne, but hair growth is usually not very bothersome. Insulin levels are usually higher than average, but development of type 2 diabetes is uncommon and development of “metabolic syndrome” is also infrequent. The diagnosis of lean PCOS is sometimes tricky, but sonography of the ovaries and measurement of testosterone levels in the blood along with a history of irregular menses is usually sufficient. Another common finding is an increased waist-to-hip ratio. Eventhough these women can appear to be skinny, their hips are usually narrow as well and their waist-to-hip ratio is frequently close to one. For women without PCOS, a ratio of 0.7 – 0.8 is usually associated with optimum fertility.
Treatment of lean PCOS is not standardized. In our experience, we have good results with the following recommendations. First, these women seem to benefit from more exercise than normal women. Excessive exercise is usually harmful to fertility in most women. In this particular situation, however, women are frequently very fit, and exercise is not stressful; in fact, it is stress relieving. Exercise also increases muscle sensitivity to insulin and naturally lowers elevated insulin levels. Since insulin promotes muscle growth, the combination appears to be synergistic. As opposed to obese women with PCOS (see below) these women seem to do well with only moderate carbohydrate restriction (if they exercise!). For some mysterious reason, many women with lean PCOS seem to shun eating protein! On more than one occasion, I have heard that these women would like to eat bread, salad, and cake before anything else. The reason for this is not understood. Perhaps, in the paleolithic times, this preference was beneficial. In our experience, if we can have these women focus on a large serving of protein and fat, then everything else seems to fall into place.
Women with Obese PCOS (a.k.a. “apple-shaped” or “famine-resistant-“ PCOS) comprise the bulk of patients seen in fertility clinics. These patients have what I call “sports car” metabolism and they require “premium fuel.” These women may present with a cluster of related diseases: metabolic syndrome, “pre-diabetes” or frank Type 2 diabetes, gall bladder disease, fatty liver, chronic heartburn, depression, and orthopedic issues. They are also at higher risk of obstetrical complications.
In the evolutionary context, these women are designed to gain weight, hold on to weight, and resist losing weight. They are the “insurance” that has protected our species against famine and times of scarcity for thousands and thousands of years. Starvation severely hinders fertility in most women. Obese PCOS’s, however, have the exact opposite reaction. They appear to blossom and their fertility seems to peak with weight loss!
Obese PCOS women generally have chronically elevated insulin levels and are at very high risk of type 2 diabetes and chronic inflammation. They tend to have very bothersome hair growth and frequently have darkening of the skin on the back of the neck, along with unappealing skin tags in the same areas. This signals chronic stress on the pancrease. Also, one frequently sees stretch marks on the abdomen with “purple tips.” This suggests chronic adrenal gland stress as well. Obese PCOS is clearly not a healthy condition!
Obese, apple-shaped women with PCOS are the ideal candidates for carbohydrate restriction. Exercise is inherently unappealing to these women and compliance with exercise regimens is abysmal in our experience. Concurrent hormone problems (especially thyroid) and frank diabetes need to be evaluated and corrected. Once obese PCOS is ruled in, the hard work of treatment begins. These women suffer from chronic global inflammation that causes most of their long term health issues. These patients require nourishment – not starvation – for successful reversal of their deteriorating health. A low carbohydrate, nutrient-dense diet is the first-line intervention in our clinic. Carbohydrate restriction has been shown consistently to reverse fatty liver changes, improve abnormal cholesterol levels, and lower inflammation and blood sugar levels. Anecdotal evidence is also accumulating that these dietary changes improve fertility and reduce “clomid failures.” Clomid is an old, safe and cheap drug that can help these women ovulate and become pregnant. Dietary changes usually allow this medication to be effective which avoids having to use more expensive and risky fertility treatments.
Treatment requires accurate diagnosis. Appropriate blood testing can rule in the diagnosis of PCOS and identify other serious problems. High hsCRP levels (a marker of inflammation) may also benefit from higher doses of omega-3 oil supplementation. One could argue that almost all Americans are omega-3 deficient, so universal supplementation is a rational treatment approach. Lipid panels do not change management so are not indicated, although they may serve as an additional marker of dietary compliance. HDL levels and LDL particle size virtually always increase and triglyceride levels uniformly fall with low-glycemic, nutrient-dense diets. This is beneficial.
Compliance is the number one obstacle to any successful dietary treatment plan. A common impediment is the absence of a gall bladder. Many patients have already had their gall bladders removed, even at a young age. These women are at a distinct disadvantage since they cannot always consume higher fat meals. Frequent smaller meals and snacks, along with a slow migration of dietary changes is usually tolerable. Portion control can be attempted, but frequent hunger can threaten success.
Socio-economic status, educational background, and poverty are also difficult headwinds to over come. High-quality foodstuffs (meats, fish, fresh produce) frequently cost more at the retail level. This may explain the association between obesity and poverty. Economies can be found, but success requires mental flexibility, access to transportation, and the ability to buy in bulk and on sale. Unfortunately, this type of “smart shopping” is out of reach for many disadvantaged patients. Bariatric surgery remains an effective treatment of last resort in patients who cannot make the necessary dietary changes. Unfortunately, long term data on health and pregnancy outcomes is still lacking. We prefer that patients undergo a restrictive procedure (i.e. lapbanding) rather than some type of bypass procedure. We do not want to replace an obesity issue with a malnutrition one!
Gil Wilshire, MD, FACOG