Does a vegetarian diet lower cancer risk?

To Vege Or Not To Vege

It’s an impressive headline: “Vegetarians Less Likely to Develop Cancer, Say Researchers” (NutraIngredients-USA).

So you could understand how someone might see that and think: Well, I love my veggies so, okay, that’s it – I’m going vegetarian.

But the world of news article headlines is a simple world of broad generalizations. The reality: This study is a mixed bag of results. So don’t overhaul your dietary habits just yet.

Big fish

Oxford University researchers followed 12 years of medical records for more than 61,000 UK residents whose diets were grouped into three categories: about 32,400 meat eaters, about 20,600 vegetarians, and about 8,500 who didn’t eat meat but included fish in their diets.

RESULTS:

  • Meat eaters: 2,204 total cancer cases
  • Vegetarians: 829 total cancer cases
  • Fish eaters: 317 total cancer cases

So overall, about 3.7 percent of the fish eaters developed cancer, about 4 percent of the vegetarians, and about 6.8 percent of the meat eaters.

Rates of stomach cancers, bladder cancers, and cancers of the lymphatic and haematopoietic tissues were significantly lower in the vegetarian group. Rates of prostate cancers and ovarian cancers were significantly lower in the fish group compared to the meat-eaters, while vegetarians didn’t appear to benefit in these two cancer categories.

Oddly, cervical cancers were much more common among vegetarians and fish-eaters compared to meat-eaters. Which is not to say that fish and vegetables actually cause cervical cancer, of course. The Oxford team cautions that none of the results imply clear cause and effect.

Starting with B…

So if you mulled the Oxford results and you’re still set on going vegetarian, there are a few details you should know before you get started.

In previous e-Alerts, HSI Panelist Allan Spreen, M.D., has noted how important it is for vegetarians to include vitamin B-12 in their supplement regimen. He states flatly that vegetarians have no way of getting this important B vitamin in adequate amounts unless they take a B-12 supplement.

So I asked Dr. Spreen what other suggestions he might offer to a strict vegetarian.

Dr. Spreen: “Besides the B-12, I’d add some conjugated linoleic acid (CLA), as that form only comes from being processed within an animal. Getting enough of the omega-3 oils in general is a problem, as the ratio tends to be more omega-6 in vegetarians (no fish).

“I’d also add some saturated fat – since butter and lard (animal fat) are out, vegetarians (especially young ones) are missing the type of fat that’s needed for cell membrane production (kind of important, as you might imagine). In that case I’d be pushing for the use of coconut oil and palm kernel oil (neither one being popular these days).

“Iron is a problem (especially since only animal sources provide iron in a form that ‘insulates’ its oxidative effects from the body within a heme ring), so I’d add an iron supplement.

“Vitamin D is no problem if the individual gets enough whole-body solar exposure daily. That’s kind of rare, unfortunately, so I’d be adding that.

“High quality protein (egg highest, milk next) is an issue. You’re only left with soy, a sad substitute (especially in young boys), but I’d have to add that.”

For a detailed rundown on problems with soy (and how to avoid them), check the e-Alert “Wrong in Soy Many Ways” (12/18/08).

Talk to your doctor or an experienced dietician before making any substantial changes in your diet or supplement regimen.

Sources:
“Vegetarians Less Likely to Develop Cancer, Say Researchers” Shane Starling, NutraIngredients-USA, 7/2/09, nutraingredients-usa.com
“Cancer Incidence in British Vegetarians” British Journal of Cancer, Vol. 101, No. 1, 6/16/09, nature.com