Could going Paleo give you cancer?

In the past several years, the Paleolithic diet (or “caveman” diet) has become a huge diet trend.

You’ve probably heard about it—and possibly even tried it for yourself. Quite a few doctors encourage it because it includes only foods we were designed to eat.

This post is on Healthwise

26 February 2015

Newsletter #477
Lee Euler, Editor

In brief, the theory is that humans were hunter-gatherers for hundreds of thousands of years, but we’ve been farmers chowing down on grains (i.e. calorie-dense carbohydrates) for only 12,000 years. Our bodies haven’t adapted to the change.

At first glance, avoiding all processed foods while increasing your intake of plants, proteins, and healthy fats appears to have no downside. But it turns out there may be a downside after all – and quite a big one.

The Paleo diet’s effects – losing weight, increasing antioxidant intake, and reducing systemic inflammation from processed foods and sugars – are all proven health benefits … and well-known ways to reduce cancer risk.

But recent studies from the University of California-San Diego have found that one key part of the Paleo diet … and the American diet in general … could be causing cancer.

Quick review of Paleo basics

The Paleo diet is based on the foods that would have been available to “cavemen” historically, including unprocessed, organic foods like fish, meat, eggs, nuts, fruit and vegetables.

The eating plan generally cuts out dairy products, grains, legumes, excess sugar and vegetable oils, with a few exceptions.

Basically, it’s a plant-based, high protein, clean fat diet.

Of the relatively few nutritional objections I’ve heard about the Paleo diet — the lack of carbohydrates, primarily — the emphasis on consuming red meat seems most concerning. As readers of this newsletter know, I think the fewer carbs you eat the better. But you have to eat something, and if you never touch a carb, red meat tends to be what you do eat.

A history of cancer

There is plenty of evidence that red meat — i.e. beef, pork, and lamb — increases your risk for cancer, heart disease, type 2 diabetes, and the sum total of deaths from all causes.

23 separate studies spanning 1986 to 2014, from populations around the world, show that red meat consumption has a positive correlation with breast, prostate, and GI tract cancers. Be aware that the GI tract category includes cancers of the esophagus, stomach, bladder, pancreas, colon and rectum. High red meat consumption even correlates with a higher risk of head and neck cancers.¹

The World Cancer Research Foundation report actually listed eating red meat in the top 10 risk factors associated with cancer worldwide. And, there is a low rate of cancer in populations that eat little to no red meat.²

Researchers tell us that red meat is an inflammatory food, but until recently they didn’t know exactly why it was causing such a problem.

Thanks to a team from University of California-San Diego, we may now have a clue why red meat causes inflammation … and therefore, cancer.

My own private theory (unbacked by studies) has been that corn-fed beef raised with hormones and antibiotics is the source of the higher cancer rates, and that organic beef may not be carcinogenic. The UC-San Diego findings cast some doubt on my idea.

The “alien sugar” hiding in your body

Researchers from UC-San Diego have been working with sialic acids — sugars found in most mammalian cells that play a fundamental role in cell communication.³

These aren’t like table sugar. Think biomolecular structure, not the white stuff that sweetens your coffee. There are four major classes of molecules: sugars, proteins, nucleic acids (DNA and RNA), and lipids (fats). Sugars are also called carbohydrates and saccharides.⁴

What’s caught their attention more specifically is the predominant sialic acid in most mammal’s cells, called N-glycolylneuraminic acid … or Neu5gc.

The weird part is that humans don’t produce this substance — we get it only from “red meat” animals, like cows, sheep, and pigs.

And – this is important – these sialic-acid-type sugars don’t lead to the usual problems associated with carbs – high blood sugar, metabolic syndrome, diabetes, etc. The reason they pose a danger is that they are foreign bodies that provoke an immune-system reaction, i.e. inflammation.

Despite its “species-specific” nature, the “red meat sugar” Neu5gc has been found circulating in almost all human blood, in our tissues, and densely packed in certain cancers.

Because it is a “non-human sugar,” our bodies have developed and are constantly generating antibodies to identify and remove the foreign substances. This causes systemic inflammation known as xenosialitis.³

The UC-San Diego researchers used a mouse model to not only prove that Neu5gc is bioavailable from red meat sources, but to prove it is a cause of systematic inflammation.

Long-term exposure caused a five-fold increase in tumor growth.⁵

“The final proof in humans will be much harder to come by,” said UCSD’s Dr. Varki of their results. “But, this may also help explain potential connections of red meat consumption to other diseases exacerbated by chronic inflammation, such as atherosclerosis and type 2 diabetes.”⁶

To be honest, I wasn’t aware of a link between diabetes and red meat consumption. But it’s possible, if red meat promotes inflammation.

We need to take this new research with a grain of salt. The findings have not yet been extrapolated to humans … and to do so may prove too difficult, and possibly unethical. This one study doesn’t settle the matter.

But I have to admit it has unsettled me, and I’m reexamining my belief that organic red meats are safe. I find it hard to ignore the evidence they found … as well as the overwhelming epidemiological evidence that red meat increases cancer and all-cause mortality.

I mostly eat chicken. But having lately gone on a very-low-carb eating plan, I’ve allowed myself to indulge in organic beef and pork more often. As I said, you have to eat something, and doing totally without carbs puts you on the spot to figure out what.

Carbs grown on farms are the easiest, cheapest and most abundantly available foods on earth. There is a reason the human population vastly increased and the first towns and cities came into being after the development of agriculture: there was more food.

The role of resistant starch

If you can’t imagine giving up red meat entirely, there may be hope …

One study found that even when doubling the recommended intake of red meat, eating 40 grams of resistant starches daily — such as bananas, beans, chickpeas, lentils, and whole grains — reduced colorectal-cancer-promoting proteins back down to baseline.

The Australian researchers believe the effect is thanks to butyrate, a beneficial short-chain fatty acid produced in the large intestine where resistant starches are fermented. Butyrate is known to promote the growth of healthy cells in the colon, while inhibiting tumor cells.⁷

However, the only “Paleo friendly” resistant starch the authors mentioned are bananas. (Personally, I see nothing wrong with eating beans, chickpeas, and lentils, but that choice is up to you.)

The bottom line

I believe following a Paleolithic diet is beneficial in many, many ways—and most people would do well to build their diets on whole, organic, plant-based nutrition with clean protein and healthy fats.

But the possible inflammatory characteristics of red meat, combined with lack of high-fiber starches that could combat inflammation and tumor growth, is reason for worry.

Until we have definitive, long-term studies on the antioxidant (and thus anti-inflammatory) properties of the fruit, vegetables and fats in the Paleo diet … and how they work in combination to mitigate oxidation and inflammation in the body … you may want to take a “better safe than sorry” approach.

Focus your protein-intake on organic white meat, such as chicken and turkey … increase your visits to the fresh fish and seafood counter (the fish low on the food chain, not the carnivorous fish that are high in mercury) … and snack on known body-healthy proteins like nuts and seeds.

You can also supplement with a clean protein powder. Look for whey

concentrate powder with no sugar or artificial sweeteners — whey isolate is overly processed and deficient in nutrients.⁸

If you’re going to eat red meat, the American Heart Association recommends limiting it to 6 ounces per day. And you should also consider a Paleo-friendly side of resistant starches like bananas or lentils.

From what I’ve seen, I’m thinking of limiting my red meat intake to one meal a week, at most.

Kindest regards,

Lee Euler, Publisher

http://www.cancerdefeated.com/could-going-paleo-give-you-cancer/3092/

Go to Healthwise for more articles