Previously I discussed how the Paleo Diet could be beneficial for couples with infertility problems. Let’s not forget infertility is a two sided coin involving health issues which may affect sexual activity and reproduction in both males and females. In this blog I will focus upon a number of recent scientific studies which confirm that male reproductive health (including sperm quality, quantity and erectile function) are closely associated with diet and overall health.
Infertility affects 10-15% of reproductive aged couples in the U.S.1, 2 as well as 60-80 million couples worldwide.3 The male contribution to this problem has been identified to be as high as 58%.4 Erectile dysfunction (ED) is estimated to affect over 100 million men internationally.5 ED is defined as the inability of a male to attain and maintain a sufficient erection for satisfactory sexual intercourse. A review of the current literature supports the notion that the typical western, junk food diet is a major contributory factor to male infertility and ED.6-8 Further, as I will shortly demonstrate, adoption of a contemporary Paleo Diet may reduce male infertility and alleviate the symptoms of ED.
Semen/Sperm Quantity and Quality
A number of large population studies,9-12 including a review of more than 100 scientific papers dating back to 1934,13 show that male semen/sperm quantity and function (motility) per ejaculation has severely declined over the past 80 years. If we go backwards in time to the 1920s or 1930s, the decline in semen quantity and quality occurred shortly after the widespread introduction of processed foods.14 Are these two facts serendipitous or are they causally related? Let’s examine the data.
We are what we eat, and it should not be surprising to know that food has the capacity to positively or adversely affect all tissues of the body14-16 including the penis, the prostate gland, the testicles, semen and male hormones (androgens) – all of which regulate normal reproductive function in males. Accordingly, changes in the western diet that have occurred since the industrial revolution and earlier14 have now been implicated in male reproductive dysfunction.
Refined sugars comprise 15-18 % of the calories in the typical U.S. diet, whereas 200 years ago, except for honey these foods were rarely or never consumed by the average citizen.14 A recent study has shown that consumption of sugar laden soft drinks impairs sperm mobility in healthy young men.17 Consequently, soft drinks or more accurately, “liquid candy” consumed on a regular basis may adversely affect your sperm’s ability to fertilize your partners egg, thereby reducing you and your partner’s chances for a successful conception. If this data doesn’t get your attention, then maybe the following information will.
Regular ingestion of soda pop and sugary soft drinks is intimately involved in ED.18 If you have bought into the Viagra commercials and wasted your monies on this pharmaceutical, there is an alternative and healthier solution – stop drinking sugar laden soft drinks and stop eating processed foods loaded with refined sugars. A good starting point would be for you to adopt the Paleo Diet which is almost totally devoid of refined sugars and processed foods.
It has long been known that ED and poor semen quality are associated with overweight and obesity, insulin resistance, cardiovascular disease, type 2 diabetes, high blood pressure19-22 and lack of exercise.23 These health issues get progressively worse as you age, as does ED.24 A good strategy to counteract obesity, insulin resistance, cardiovascular disease, type 2 diabetes and high blood pressure is the Paleo Diet.14-16, 25 You may just find that your ED and Viagra will become things of the past.
Over the years since Paleo has increasingly come into the public eye, more and more versions of Paleo Diets have been put forth by people from all walks of life. One issue is dairy – should you or should you not include milk, yogurt, cheese and other dairy products in your modern day Paleo Diet? If we look at the anthropological and evolutionary data, the answer is a resounding no!26 Ancestral hunter gatherers could have never included dairy products in their daily menus because it is nearly impossible to approach large, wild mammals – much less milk them.
Dairy products comprise about 12% of the average daily caloric intake in the U.S. diet,14 yet these foods may have a number of nutritional factors which adversely impact human health14-16, 27-30 including male reproductive function. The data speaks for itself.
A recent epidemiological study31 in healthy, physically active young men showed that increased total dairy intake was related to impaired sperm morphology, particularly for full fat dairy products. A similar study in men attending a fertility clinic demonstrated that increased cheese intake was related to lower sperm concentrations.32
At first, most people wouldn’t have a clue why milk and dairy consumption should have anything to do with male reproductive health. But, a deeper dig into PubMed reveals that cow milk ingestion by humans has long been associated with male reproductive disorders.33, 34 One of the suspected mechanisms is that cow’s milk represents a major route of human exposure to exogenous estrogens,35, 36 a likely factor in male infertility and ED.37, 38 Further, as our research group has pointed out, milk and yogurt yield low glycemic loads, but paradoxically increase blood insulin concentrations39 and produce insulin resistance in young boys.40 Accordingly consumption of milk and dairy products, have the potential to adversely affect male reproductive function by increasing circulating blood concentrations of female hormones while simultaneously altering insulin metabolism in a fashion similar to chronic diseases of insulin resistance known to present concurrently with ED and poor semen quality.19-22
We’re not done with milk, dairy and male reproductive health just yet. Milk and dairy products are concentrated sources of calcium which impair absorption of zinc and iron.40, 41 So if you decide to put a slice of cheese on your grilled burger, you unknowingly will severely reduce absorption of the zinc and iron normally present in ground beef. The number one nutrient most lacking in the U.S. diet is zinc, and 73% of all U.S. citizens do not meet the DRI (dietary reference intakes) recommended for zinc.14 It turns out that zinc is an absolutely essential dietary element required for normal sperm development and function.42 Low blood concentrations of zinc in males are associated with poor sperm quality and increase the risk for infertility.43, 44 Plant foods (such as whole grains and legumes) are poor sources of zinc because this mineral is bound to a compound called phytate which reduces its absorption by as much as 75% in the intestine.45, 46 Further, the type of zinc found in animal foods is highly absorbable. Beef is a great dietary source of zinc – eat it regularly (particularly the grass produced variety) and your blood concentrations of zinc will rise. One of the richest sources of zinc is found in oysters, a food which historically has been associated with increased male libido and fertility.
Salt, Nitric Oxide and Erectile Dysfunction
In the “Paleo-sphere” there seems to be widespread approval of sea salt as an acceptable ingredient in Paleo recipes and menus. As I have laboriously pointed out, nothing could be further from the truth – our Stone Age ancestors rarely or never added salt to their foods.47 Sea salt maintains the same adverse health effects as does commercially manufactured salt. Both should be avoided in contemporary Paleo Diets for a wide variety of health reasons including erectile dysfunction.
A increasing body of scientific research demonstrates that high salt diets impair a normal erection. Most men eating an average American diet are completely unaware that they are consuming a high salt diet. We have shown that the typical western diet contains 10 grams of salt per day, whereas our hunter gatherer ancestors ate a tenth of this amount.14 The majority of our present day salt intake comes from processed foods, particularly breads and cereals.14
Comprehensive experimental studies in both humans and animals demonstrate that salt ingestion causes a profound reduction in nitric oxide (NO) in vascular (blood vessels) tissues throughout the body, including the penis.47 Normal levels of NO in the penis bloodstream are required to sustain a sufficient erection for intercourse, without which ED may occur.48-50
OK – let’s review. Salt which we get mainly from processed foods and cereals severely reduces NO in blood vessels, including the penis. An erection required for intercourse cannot occur without normal blood concentrations of NO. So any nutritional factor, such as salt, which reduces synthesis and production of NO should be avoided, if your goal is to maintain a fully erect penis during intercourse. Virtually all contemporary processed foods have high salt contents14– another good reason to adopt The Paleo Diet.
Therapeutic Foods for Erectile Dysfunction
A caveat to this concept are foods which increase NO production and promote normal erectile function. These are the foods which you should focus upon. You don’t have to look far to discover these healthful NO eliciting foods, as they are nothing less than the quintessence of The Paleo Diet.
Omega 3 fatty acids stimulate NO release.51 The Paleo Diet is rich in long chain omega 3 fatty acids because it encourages regular consumption of fatty fish (salmon, mackerel, herring, and other seafood), free ranging meats, poultry and eggs. Additionally antioxidants such as zinc in the form of glutathione boost NO production while preventing its breakdown.51 Contemporary Paleo diets are both high in omega 3 fatty acids and zinc, much more so than the USDA recommended Food Pyramid/My Plate.52 Foods high in antioxidant vitamins and minerals (particularly zinc and selenium) and folic acid support the release of NO and may prevent degradation in sperm quality.43, 44, 51, 53-58 The Paleo Diet is rich in fresh fruits and veggies making up approximately 30-45% of calories52 and inherently is high in antioxidant vitamins, minerals and phytochemicals, whereas the typical U.S. diet contain less than 10 % of its daily calories as fruits and vegetables.14
A Few Final Thoughts and Recommendations
As I have indicated time and again, The Paleo Diet is not a diet at all, but rather a lifelong program to maximize health and well being by consuming, natural living foods and avoiding processed foods. All body tissues (be they male or female), including our reproductive organs respond positively when they are provided an environment and milieu consistent with that which shaped our species over millions of years of evolutionary wisdom. Male reproductive function including ED can improve by eliminating the ubiquitous processed foods in the standard American Diet. You can go a long way in improving your erection and sperm quantity and quality by eliminating refined sugars, high glycemic load carbohydrates, dairy products and salted foods. Here are a few additional scientific tidbits of advice which add credence to The Paleo Diet and men’s reproductive health.
With contemporary Paleo Diets, I advise you to avoid processed meats like bacon, sausages, bologna, salami, prosciutto, liverwurst, hot dogs, ham, and the like. All of these meats are incredibly high in salt and typically maintain a fatty acid profile that looks nothing like fresh, unadulterated wild or grass produced meats59, 60 – to say nothing of the preservatives and additives which are part of these meats.
A recent study indicates consumption of processed meats in healthy young men is associated with a lower sperm count.61
Trans Fatty Acids
I’m sure that I’m not going to get much disagreement in the Paleo community when I say that we should avoid trans fatty acids produced via the hydrogenation process used to manufacture margarines, shortenings and the vegetable fats found in many processed foods. These fats may increase shelf life of processed foods, yet have been known for more than two decades to have adverse effects upon human health.14 If you regularly eat a doughnut, bagel or pancake at breakfast or a sandwich at lunch you will most likely be consuming a trans fatty acid (trans elaidic acid) which has been shown to be related to a reduced sperm count in healthy men.62
If you voluntarily decide to eliminate or reduce animal foods from your diet via vegetarian or vegan protocols, you will almost certainly become deficient in vitamin B12. As I have previously pointed out, B12 deficiencies universally result in elevated homocysteine concentrations throughout the body, including the testicles and ovaries which impair fertility for both men and women.
A recent study evaluating vitamin B12 concentrations in infertile couples had this to say, “Thirty nine percent of all men with an abnormal semen analysis had cobalamin (vitamin B12) deficiency.”
Infertility and ED are diseases which have increasingly been associated with the same dietary and environmental factors that elicit the chronic diseases of civilization (obesity, overweight, cardiovascular disease, type 2 diabetes, hypertension, acne, gout and a number of cancers). The same protective dietary measures (The Paleo Diet) that reduce or eliminate symptoms of the diseases of civilization almost certainly will promote positive reproductive function in men of all ages.
Loren Cordain, Ph.D., Professor Emeritus
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