Just when people are at feeling (justifiably) entitled to feel OK about eating meat again, out comes a study that “associates” consumption of meat with type 2 diabetes. It was published in the American Journal of Epidemiology and was part of the Singapore Chinese Health Study. Here’s the gist:
—Over 63,000 Chinese adults, ages 45-74 years
—There were two interviews during follow-up of just under 11 years to determine type 2 diabetes
—Dietary pattern determined only once – at the start, by a food-frequency questionnaire
—The variables: intake of poultry, red meat, seafood and incidence of type 2 diabetes upon follow-up.
They divided the subjects into four groups based on intake of shellfish, poultry, and red meat. Then they compared the groups with the lowest intake of meat/poultry/shellfish with groups that had the highest intakes.
Here’s where things get interesting, but first:
There are two ways iron exists in food. Iron is either part of hemoglobin (called “heme iron”), as in the case of animals, or it’s bound to other compounds (called “non-heme iron”), as with plants. Compounds like phytates in plants bind to iron to make it less absorbable. Eating plant iron with an acid, like having spinach with a vinaigrette dressing, will help liberate some of the iron, but in general, heme iron is more available to the body.
How much iron do we need each day? Adults need 12 mg/day and women of child-bearing age need 18 mg/day, because they lose iron each month they menstruate.
The study data are “noisy”
This means the study has limitations that prevent drawing strong conclusions. To be fair, he study’s authors were pretty responsible in pointing out some of the limitations of their study. Most notably:
- Dietary pattern was taken at the beginning and never again. So, what you had for dinner on a Tuesday night 11 years ago predicts your health now? You might be able to get statistics from this data, but drawing any realistic conclusions is making a Grand Canyon leap. People’s diets change over 11 years!
- Activity patterns were also assessed only once, at the beginning of the study.
- Those who ate the most red meat ate averaged only about 53 grams daily – less than two ounces! And they still ate more seafood than meat.
- Those who ate the most seafood also averaged about 33 grams of red meat daily — a little over an ounce! So differences between the HIGHEST and LOWEST consumption of red meat was only 20 grams – about 2/3 of an ounce.
- Different meat types were assessed (beef, pork, lamb, etc.), but not cuts of meat, or parts of poultry (legs have more heme iron than breast) or dietary fat. Pork belly has lots more fat than pork loin, for instance.
With the difference between the highest fish-eaters and the highest meat eaters being only 20 grams of meat, the difference may be statistically significant but not clinically (“real life”) significant. The “associations” these studies talk about don’t mean “cause-and-effect” but consumers don’t often understand that. and the headlines don’t help much. To get the facts you usually have to read beyond headlines.
My take-away from this study? Not a whole lot.
And the authors pretty much agree with me, noting, “We do not perceive any reason for meat intake to be related to the likelihood of disease diagnosis in our study population.” Simply put, this study failed to connect meat intake with type 2 diabetes. Game over.
Seafood absolutely is great food, but meat and poultry are also nutrient-rich. Some tips for eating meat and poultry well:
- Go leaner whenever possible.
- Keep portions real. Even 4 ounces of lean meat is going to be loaded with enough protein for your meal.
- Keep half your plate veggies and fruits.
- Include a whole grain or a starchy vegetable.
- Keep added fat reasonable. Olive oil or canola are good choices, rather than butter or coconut oil.