Nutrition for Fertility

Food choices impact every aspect of health; how you felt yesterday, how you will feel today and how you may feel tomorrow. Many studies have illustrated how nutrition, exercise, stress management, and a good's night sleep can impact health, longevity, fertility, pain and even anxiety. While a healthy diet is considered paramount for optimal health, unhealthy eating habits plague the United States. 3 out of every 4 individuals do not meet the Dietary Guidelines for vegetables, fruit, dairy and oils (1). Additionally, most Americans exceed the recommendations for added sugars, saturated fats, and sodium. Certainly, "Big Food" has an influence on what recommendations are set forth within the Dietary Guidelines, but the reality is that most Americans do not eat real food (2).

As discussed in previous blogs, the conversations around diet and nutrition are broad, from plant based to diets based in healthy fats and animal protein. If you have read our other blogs, this may sound like a broken record. However, this idea is central to optimal health, eat real food. It wasn't until the 20th century, that food started to become an industrialized process. In the 1960's there was another dramatic shift in nutrition; the idea that diets high infat and cholesterol were the cause of chronic disease such as heart disease (3). These radical ideas lead us to a lifestyle that demonized animal fat and praised vegetable oils and carbohydrates. Interestingly enough, the National Health and Nutrition Examination Survey (NHANES) found that the prevalence of obesity among adults aged 20–74 years has increased 19.2% in men and 16.6% in women from the first NHANES study (1971–1975) to the second NHANES 2003–2004 (4).

For those who want to "nerd out" on the NHANES study (click here). For those not so into statistics the summary of the NHANES study is as follows; the percentage of energy from carbohydrates increased uniformly across both men and women and across the normal-weight, overweight, and obese groups, while the percentage of energy from fats has decreased uniformly across both men and women (5).

In other words, as fat consumption was reduced and carbohydrate intake increased, obesity became more prevalent.

Balanced Diet - Not so Fast

A balanced diet by definition is a diet that helps to maintain or improve one's health. The scientific definition would be a diet that provides all of the essential nutrients such as vitamins and minerals.

While 75% of Americans claim to eat a balanced diet (6), ironically the opposite is true. The central idea I introduced earlier, eat real food, is not the reality. This idea of a"balanced diet" in the US is that 57.9% of energy comes from an ultra-processed food intake (7). At first glance this number simply doesn't seem possible, but then I looked into what defines an ultra-processed food.

The authors classified ultra processed as "formulations of several ingredients which, besides salt, sugar, oils and fats, include food substances not used in culinary preparations, in particular, flavours, colours, sweeteners, emulsifiers and other additives used to imitate sensorial qualities of unprocessed or minimally processed foods and their culinary preparations or to disguise undesirable qualities of the final product" (7).

After reading the authors definition, I wanted to go to the grocery with the goal to look at what people buy. While my "observational experiment" is lacking official statistical data I still able to come to the following conclusion. Even at a "healthy grocery store", most of the food in each person's cart was simply not real food. It was pretty clear to me that if I was able to talk to my great-great grandparents they would not recognize the packaged food in the store.

Micronutrient Deficiencies

Despite the fact so many processed foods are fortified with vitamins and minerals. Many Americans are still not meeting the micronutrient intake requirements from food alone (13,14). This is likely due to the fact that ultra-processed foods are poor sources of vitamins and minerals. While a high quality supplement can help to off-set nutrient deficiencies, the optimal avenue would be to receive these nutrients the way nature intended, within real food.

The two subpopulations that would be recommended to supplement, regardless of if they are consuming a nutrient rich diet, would be those who are pregnant or children younger than 5 years of age. As these populations are most at risk for nutrient deficiencies. Additionally, if you are looking to became pregnant, it's never a bad idea to "preload" these nutrients prior to conception. If you are wondering how to preload, typically it's recommended to start eating a nutrient dense diet and continue these eating habits throughout your pre and postnatal time. Additionally, it's recommended to supplement with a high quality prenatal vitamin, cod or fish oil and various other minerals and vitamins as determined by your health care professional. For an example of nutrient dense diet especially when it comes to boosting your fertility check out the work of Weston A Price. In summary, the diet is focused on foods such as full fat dairy, fruit and vegetables, fish roe, pastured meats, eggs and organ meats. The research on their website is very interesting and definitely worth checking out.

"The Western Diet"

As we have already learned the western diet is plagued with an abundance of calories and suboptimal levels of nutrients. Lately, there has been an increasing number of researchers looking to determine how the western diet could be impacting fertility. The idea of taking measures to improve fertility, may seem odd as we have been having children for, well forever. However, as previously discussed, infertility impacts at least 15% of couples worldwide. The health, diet, and lifestyle choices of both men and women should be taken into consideration.

1) Body Fat: The idea that fat makes you fat is wrong, it's the excess calories of all macronutrients (carbs, fat, and protein) that are promoting weight gain. This raises the question of how does body fat impact fertility? The answer is body fat impacts fertility in a vast number of ways. Too low, and hormones such as testosterone will drop dramatically, such as in this 2013 case study (15). While most studies demonstrate that low testosterone within men isn't going cause abnormalities or sperm motility issues - it has been suggested that there may be a reduced sperm count.

On the other hand, having too much body fat isn't ideal either. A 2020 study in Metabolism concluded, a"n individual will experience, increased oxidative stress, lipotoxicity and disturbances in the concentrations of adipokines. These changes can directly affect the gonads, peripheral reproductive organs and the embryo" (16). Obesity within women has been thought to alter the hypothalamic-pituitary-ovarian (HPO) axis. Multiple studies have demonstrated that obese women have increased time to pregnancy. In large cohort study of Danish women, the study demonstrated that pregnancies showed a decline in fecundability (1 month conception) ratios with increasing body mass index (BMI) (17,18). Even in the absence of ovulatory dysfunction such as PCOS, obese women remain subfertile. In 3,000 Danish women, the probability of spontaneous conception declined linearly with each BMI point >29 kg/m2 (18).

Eating for Fertility & Fertility Diets

Male Infertility Foods

Semen quality has decreased substantially in the last few decades. According to a recent meta-analysis that included more than 185 studies, total sperm count has declined by 50% to 60% from 1973 to 2011 in Western countries. A 2020 study with sample size of nearly 3000 Danish men and found that a diet high in processed foods such as pizza, chips, processed meats, etc adversely impacted sperm quality (19). The authors concluded "Our findings support the evidence that adhering to generally healthy diet patterns is associated with better semen quality and more favorable markers of testicular function. Because diet is modifiable, these results suggest the possibility of using dietary intervention as a potential approach to improving testicular function in men of reproductive age." (19) Learn more about male infertility

As for regarding specific foods, I believe it's important to note that observational studies may prove associations but not causation, and thus randomized control trials should be performed. But, without further avail here's a list of male infertility foods:

1) Omega 3 rich food - wild salmon, sardines, herring, pastured meats, etc

2) Leafy Greens - kale, collards, mustard, romaine, etc

3) Pastured eggs, meat, and organ meats

4) Full fat pastured dairy and cheese

5) Misc fruits, vegetables, nuts, & seeds: Broccoli, blueberries, strawberries, Brazil nuts, pumpkin seeds, etc

Female Infertility Foods

A number of gynecological and systemic diseases can affect a woman's ability to conceive. Additionally, there are a number of lifestyle factors and environmental conditions that can impact fertility as well. A stressful job, environmental pollutants i.e. mercury and/or an unhealthy diet can negatively impact fertility (20). The following nutrients and vitamins were positively correlated to increase a woman's chances of getting pregnant: folic acid, vitamin b12, omega 3 fatty acids and nutrient dense diets such as Mediterranean diet (21).

The Mediterranean diet is often praised for being high in antioxidants, high quality protein and fat as well as vitamins and mineral necessary for optimal health and longevity. Antioxidants are the component of the Mediterranean diet that often receive the highest praise. Antioxidants are nutrients that assist with fighting inflammation and neutralizing free radicals. Free radicals have an unpaired valence electron and damage cellular health and DNA. Antioxidants donate electrons to stable the molecule. This process occurs multiple times every second of the day. Many lifestyle, dietary and environmental factors can impact how many free radicals are produced within the body. Both sperm and the egg are highly sensitive to oxidative stress caused by free radicals. Therefore increasing antioxidants can help to protect the egg and sperm from possible corresponding damage. To learn more about foods high in antioxidants head over to the USDA ORAC (Oxygen Radical Absorbance Capacity) database (Keep in mind units are per 3.5oz).

Summary

Researchers, scientists, and health advocates may spend forever looking for a one size fits all diet. The reality is that diet is right beneath our nose, eat real food. While eating real food may hardly seem like a diet, the idea of eating nutritious foods in America is. Americans consume an abundance of calories and receive suboptimal levels of nutrients, due to the fact that nearly 60% of the diet comes from ultra-processed foods. By shifting our nations diet from an ultra-processed junk food paradise to a diet that is based in real foods, we may be able to to reduce obesity, improve fertility, and stop many of the chronic diseases we suffer today.

Do you have questions, thoughts, or comments about how to improve fertility? Leave them below, and I will reply!

References:

1) https://health.gov/our-work/food-nutrition/2015-2020-dietary-guidelines/guidelines/chapter-2/current-eating-patterns-in-the-united-states/

2) https://blog.ucsusa.org/karen-perry-stillerman/big-food-companies-spend-big-money-in-hopes-of-shaping-the-dietary-guidelines-for-americans

3) https://www.kqed.org/stateofhealth/236447/sugar-industry-funded-1960s-harvard-research-that-blamed-heart-disease-on-fat

4) Ogden  CL,  Carroll  MD,  Curtin  LR,  McDowell  MA,  Tabak  CJ,  Flegal  KM. Prevalence of overweight and obesity in the United States, 1999–2004. JAMA 2006;295:1549–55.

5) Gregory L Austin, Lorraine G Ogden, James O Hill, Trends in carbohydrate, fat, and protein intakes and association with energy intake in normal-weight, overweight, and obese individuals: 1971–2006, The American Journal of Clinical Nutrition, Volume 93, Issue 4, April 2011, Pages 836–843, https://doi.org/10.3945/ajcn.110.000141

6) https://www.npr.org/sections/thesalt/2016/08/03/487640479/75-percent-of-americans-say-they-eat-healthy-despite-evidence-to-the-contrary

7) Martínez Steele E, Baraldi LG, Louzada MLDC, et alUltra-processed foods and added sugars in the US diet: evidence from a nationally representative cross-sectional studyBMJ Open 2016;6:e009892. doi: 10.1136/bmjopen-2015-009892

8) https://newsinhealth.nih.gov/special-issues/eating/sweet-stuff

9) Guideline: sugars intake for adults and children. Geneva: World Health Organization, 2015.

10) Canadian Heart and Stroke Foundation Position Statement, August 2014. http://www.heartandstroke.com/site/c.ikIQLcMWJtE/ b.9201361/k.47CB/Sugar_heart_disease_and_stroke.htm

11) Johnson RK, Appel LJ, Brands M, et al. American Heart Association Nutrition Committee of the Council on Nutrition, Physical Activity, and Metabolism and the Council on Epidemiology and Prevention. Dietary sugars intake and cardiovascular health: a scientific statement from the American Heart Association. Circulation 2009;120:1011–20.

12) Scientific Report of the 2015 Dietary Guidelines Advisory Committee. http://www.health.gov/dietaryguidelines/2015-scientific- report/PDFs/Scientific-Report-of-the-2015-Dietary-Guidelines- Advisory-Committee.pdf

13)Fulgoni VL, 3rd, Keast DR, Bailey RL, Dwyer J. Foods, fortificants, and supplements: Where do Americans get their nutrients? J Nutr. 2011;141(10):1847-1854. 

14) Bailey RL, Fulgoni VL, 3rd, Keast DR, Dwyer JT. Examination of vitamin intakes among US adults by dietary supplement use. J Acad Nutr Diet. 2012;112(5):657-663 e654.

15) Rossow LM, Fukuda DH, Fahs CA, Loenneke JP, Stout JR. Natural bodybuilding competition preparation and recovery: a 12-month case study. Int J Sports Physiol Perform. 2013 Sep;8(5):582-92. doi: 10.1123/ijspp.8.5.582. Epub 2013 Feb 14. PMID: 23412685.

16) The effect of excess body fat on female and male reproduction Mintziori, Gesthimani et al. Metabolism - Clinical and Experimental, Volume 107, 154193

17) Gesink Law DC, Maclehose RF, Longnecker MP. Obesity and time to preg- nancy. Hum Reprod 2007;22:414–20.

18) van der Steeg JW, Steures P, Eijkemans MJ, Habbema JD, Hompes PG, Burggraaff JM, et al. Obesity affects spontaneous pregnancy chances in subfertile, ovulatory women. Hum Reprod 2008;23:324–8.

19) Nassan FL, Jensen TK, Priskorn L, Halldorsson TI, Chavarro JE, Jørgensen N. Association of Dietary Patterns With Testicular Function in Young Danish Men. JAMA Netw Open. 2020;3(2):e1921610. doi:10.1001/jamanetworkopen.2019.21610

20) Silvestris, E., Lovero, D., & Palmirotta, R. (2019). Nutrition and Female Fertility: An Interdependent Correlation. Frontiers in endocrinology, 10, 346. https://doi.org/10.3389/fendo.2019.00346

21) Gaskins AJ, Chavarro JE. Diet and fertility: a review. Am J Obstet Gynecol. 2018 Apr;218(4):379-389. doi: 10.1016/j.ajog.2017.08.010. Epub 2017 Aug 24. PMID: 28844822; PMCID: PMC5826784.