Processed Meats May Affect Male Fertility

Processed Meat

Story at-a-glance -

  • Men who ate the least amount of processed meat had a 28 percent higher rate of fertilization during IVF compared to those who ate the most
  • Those who ate the most poultry (and presumably less processed meats and possibly overall healthier diet) had a 13 percent higher fertilization rate than men who ate the least
  • Separate research showed people who ate the most processed meats increased their risk of dying early by 44 percent

By Dr. Mercola

Meat can be a healthy choice in your diet, provided it’s grass-fed and organic. The way the meat is raised – what it eats, where it lives, and whether it has access to the outdoors – make a major difference in whether it’s a healthy food or a disease-promoting one.

Aside from the source and growing conditions, how the meat is prepared is another major factor in its health potential. While a whole pastured chicken simmered in a pot of water to make bone broth is highly nourishing, eating chicken raised in a concentrated animal feeding operation (CAFO) and processed into lunchmeat or a hot dog is decidedly not.

On the scale of meat healthiness, processed meats rank consistently near the bottom, such that they should rarely be consumed, if at all. Adding to their laundry list of health risks, a new study has linked such meats to problems with men’s fertility.

Processed Meats Might Worsen Male Fertility

In a study of 141 men undergoing in vitro fertilization (IVF) with their partners, no association was found between total meat consumption and successful fertilization through IVF.

However, men who ate the least amount of processed meat (including sausage, bacon, and canned meat products) had a 28 percent higher rate of fertilization during IVF compared to those who ate the most.

Those who ate the most poultry (and presumably less processed meats and possibly overall healthier diet) also had a13 percent higher fertilization rate than men who ate the least.

It’s unclear by what mechanism processed meats may interfere with fertility, and the study couldn’t prove a cause-and-effect link. Dr. Elizabeth Kavaler, a urology specialist at Lenox Hill Hospital in New York City, told WebMD:1

"Perhaps it is not the meat that is the problem, but the dietary choices that men who eat bacon make. Healthier dietary choices usually correlate with a healthier lifestyle, which may overall increase fertility outcomes.

…One of the reasons the study may have found more successful outcomes in the men undergoing fertility treatments who ate chicken over bacon is that chicken-eaters may have an overall healthier diet and lifestyle than bacon-eaters.”

This could be the case, although many other studies have also linked processed meats with ill health effects, so it wouldn’t be surprising if infertility was among them.

Processed Meats Expose You to at Least Three Cancer-Causing Substances

Processed meats are those preserved by smoking, curing, or salting, or the addition of chemical preservatives. This includes bacon, ham, pastrami, salami, pepperoni, hot dogs, some sausages, and hamburgers (if they have been preserved with salt or chemical additives) and more.

Particularly problematic are the nitrates that are added to these meats as a preservative, coloring, and flavoring. The nitrates found in processed meats are frequently converted into nitrosamines, which are clearly associated with an increased risk of certain cancers.

It's for this reason that the USDA actually requires adding ascorbic acid (vitamin C) or erythorbic acid to bacon cure, as it helps reduces the formation of nitrosamines.2

Meat cooked at high temperatures, as many processed meats often are, can also contain as many as 20 different kinds of heterocyclic amines, or HCAs for short. These substances are also linked to cancer.

In terms of HCAs, the worst part of the meat is the blackened section, which is why you should always avoid charring your meat and never eat blackened sections.

Heating meat at high temperatures also appears to increase the formation of nitrosamines, with well-done or burned bacon having significantly more nitrosamines than less well-done bacon.

So at the very least you will want to surely avoid eating hot dogs, bacon, or sausages that are charred and very well done. Many processed meats are also smoked as part of the curing process, and smoking is a well-known cause of carcinogenic polycyclic aromatic hydrocarbons, which enter your food during the smoking process.

There may be other factors at play as well, but at the very least it's known that eating processed meats exposes you to at least three cancer-causing substances: nitrates and nitrites (leading to nitrosamines), heterocyclic amines, and polycyclic aromatic hydrocarbons.

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What Are the Health Risks of Eating Processed Meats?

A 2007 analysis by the World Cancer Research Fund (WCRF) found that eating just one sausage a day can significantly raise your risk of bowel cancer.3 Specifically, 1.8 ounces of processed meat daily – about one sausage or three pieces of bacon – raises the likelihood of the cancer by 20 percent.

Other studies have also found that processed meats increase your risk of colon, bladder, stomach, and pancreatic cancers. According to the American Institute for Cancer Research (AICR):

“Research suggests that regularly eating even small amounts of cold cuts, bacon, sausage, and hot dogs increase colorectal cancer risk, which is why AICR recommends avoiding these foods, except for special occasions…

The risk continues to rise as processed meat consumption increases. Studies show that compared to eating no processed meat, eating 3.5 ounces every day – a large hot dog – increases colorectal cancer risk by 36%.”

Research from the Harvard School of Public Health (HSPH) also revealed that eating processed meats increased the risk of heart disease by 42 percent and the risk of type 2 diabetes by 19 percent. Such links were not found among those eating unprocessed red meat.4

The increased risks came from relatively low amounts of processed meat, such as 1 to 2 slices of deli meats or one hot dog daily. A large study of nearly 450,000 people further revealed that those who ate the most processed meats increased their risk of dying early by 44 percent.5

Premature deaths could be slashed by 3 percent simply by people eating less processed meats, according to the researchers, who recommended limiting such meats to less than one ounce a day. They noted:

Significant associations with processed meat intake were observed for cardiovascular diseases, cancer, and 'other causes of death.’”

Are Nitrate-Free Processed Meats a Healthier Option… And What About Nitrates in Vegetables?

Many are confused about nitrates and nitrites, so let me clear up the confusion. Nitrates are present in many vegetables, such as beets, celery, lettuce, spinach, and most other leafy green vegetables. When you eat nitrates, your body converts a small percentage of them into nitrites.

Nitrites and nitrates are not inherently bad for you — in fact, they are the precursor to nitric oxide (NO), which lowers your blood pressure and exerts mild anti-inflammatory effects.

Sodium nitrite is a synthetic preservative added to meats like hot dogs to help them maintain that nice pink color. The problem is, in the presence of heat — especially high heat — nitrites can combine with amines in processed meat to form nitrosamines, and it's these that are carcinogenic.

Processed meats are far more prone to nitrosamine formation than vegetables, due to being higher in amines and intensively heat processed.6 As mentioned, vitamin C inhibits some of the nitrosamine formation. Vegetables contain more vitamin C, beta-carotene, and other antioxidants, which is another reason why the nitrates in vegetables don't cause a problem.

According to the University of Minnesota Extension, around 90 percent of the nitrite in your body comes from vegetables, while just 10 percent comes from processed meats.7

Natural or organic hot dogs advertised as nitrate-free may not be much lower in nitrite — and some may even be higher than conventional hot dogs. Companies that label their products natural or organic must use natural sources of the preservatives, which usually come in the form of celery powder, celery salt, or celery juice, as celery is naturally high in nitrate, plus a starter culture of bacteria. This transforms the nitrate found naturally in the celery salt into nitrite, which cures the meat.

A 2011 study published in The Journal of Food Protection found that natural hot dogs had anywhere from one-half to 10 times the amount of nitrite of conventional hot dogs.8 A similar scenario exists for bacon. So, buying organic nitrate-free hot dogs is not necessarily going to reduce your nitrate exposure — although it will likely result in a higher quality food product in many other respects.

Not All Meat Should Be Avoided…

While processed meats are better off avoided, organic, pastured meats can be a healthy part of your diet. Some of the benefits of grass-fed and grass-finished beef, for instance, include higher levels of conjugated linoleic acid (CLA) and other healthy fats. It also has a more balanced ratio of omega-3 to omega-6.

Modern food, in which processed foods and vegetable oils dominate, has led to a dramatic increase in omega-6 over omega-3. Compared to a century ago, we now have 100,000 times higher intake of omega-6, which does not bode well from a health perspective. Substituting processed vegetable oils with healthy animal fat is a good approach that will help optimize your health.

It's important to recognize that while the USDA 100% Organic label is good, it's not necessarily a guarantee that the meat has been grass-fed and finished. In fact, the organic label is costly for ranchers, and many actually raise their cattle in ways that provide superior beef compared to beef bearing the organic label. In my mind, a truly grass-fed, grass-finished product is superior to organic.

Unless labeled as 100% grass-fed, virtually all the meat you buy in the grocery store is CAFO beef, and tests have revealed that nearly half of the meat sold in US stores is contaminated with pathogenic bacteria — including antibiotic-resistant strains.

Grass-fed beef is not associated with this high frequency of contamination, and their living conditions have everything to do with this improved safety. This doesn’t only apply to beef, of course. It also applies to poultry, which should be organic and pasture-raised (or free-range certified), as well as fish, which should be wild-caught – not farm-raised.

Where to Find Naturally Raised Healthy Meat

Currently, meat in supermarkets will be labeled 100% grass-fed if it came from pasture, but if it contains no label it’s probably CAFO-raised. An alliance of organic and natural health consumers, animal welfare advocates, and anti-GMO activists are working together to tackle the next big food labeling battle: meat, eggs, and dairy products from animals raised on factory farms, or CAFOs.

This campaign, which aims to have CAFO foods labeled, includes a massive program to educate consumers about the negative impacts of factory farming on the environment, on human health, and on animal welfare, and hopes to organize and mobilize millions of consumers to demand labels on beef, pork, poultry, and dairy products derived from these unhealthy and unsustainable so-called “farming” practices.

In the meantime, you can boycott food products from CAFOs and choose to support farmers who produce healthy pastured grass-fed meat, eggs, and dairy products using humane, environmentally friendly methods. You can do this not only by visiting the farm directly, if you have one nearby, but also by taking part in farmer's markets and community-supported agriculture programs, many of which offer grass-fed meats. The following organizations can also help you locate grass-fed beef and other farm-fresh foods in your local area, raised in a humane, sustainable manner.

Where to Buy Locally Grown Food

You May Need Less Animal Protein Than You Think…

There's no doubt that high-quality protein is an important part of any diet. However, you do need to be careful to not consume too much. Please understand that the average American consumes anywhere from three to five times as much protein as they need. Protein is generally encouraged as being a healthy choice, especially if you are swapping it for refined carbs, but I believe it is the rare person who really needs more than one-half gram of protein per pound of lean body mass. Those who are aggressively exercising or competing and pregnant women should have about 25 percent more, but most people rarely need more than 40 to 70 grams of protein a day.

To determine your lean body mass, find out your percent body fat and subtract it from 100. So if you are 20% body fat you would have 80% lean body mass. Just multiply that by your current weight to get lean body mass. For most people, this means restricting protein intake from 35 to 75 grams a day. As mentioned, pregnant women and those working out extensively need about 25% more protein than this.

When you consume protein in levels higher than recommended above, you tend to activate the mTOR (mammalian target of rapamycin) pathway, which can help you get large muscles but may also increase your risk of cancer. There is some research that suggests the "mTOR gene" is a significant regulator of the aging process, and suppressing this gene may be linked to longer life. Generally speaking, as far as eating for optimal health goes, most people consume too much low-quality protein and carbohydrates, and not enough healthy fat. So while organic pastured meat is healthy to include in your diet, you don’t need to overdo it.