New Study: Whole Grains Are Healthful

Reconstruction of Neanderthal mealtime, from Neanderthals Carb Loaded, Helping Grow Their Big Brains, Science, 10 May 2021.
Whole grains, healthful then, healthful now.

This is a follow-up from last Thursday’s post about our early human and Neanderthal ancestors who ate a starch-rich diet, “so much starch that it dramatically altered the composition of their oral microbiomes.” It also grew the size of their brains. It upends our notion that Neanderthals ate mostly animal food. That pivotal study found that they, and their ancestors (and ours), were cooking grains 600,000 years ago!

Anyway, back to this study:

Whole- And Refined-Grain Consumption And Longitudinal Changes In Cardiometabolic Risk Factors In The Framingham Offspring Cohort, The Journal of Nutrition, 13 July 2021

It found that replacing refined grains (RG) with whole grains (WG) was linked to smaller increases in waist size, blood glucose, and blood pressure as participants aged.

Refined grains included refined cold ready-to-eat breakfast cereal (defined as containing <25% whole grains by weight), cooked breakfast cereal (not oatmeal), white bread, English muffins, bagels, muffins, biscuits, white rice, pasta, pancakes, waffles, crackers, and pizza.

Whole grains included foods made from barley, brown rice, brown rice flour, buckwheat groats, bulgur, cornmeal, corn flour, millet, oats, oat flour, rye, rye flour, and whole wheat flour.

Mechanisms:

  • WG is high in dietary fiber, which can have a satiating effect, and soluble fiber, in particular, may have a beneficial effect on blood lipids. Evidence from randomized controlled trials has demonstrated the cholesterol-lowering effect of beta-glucan found in whole grain oats.
  • The slower digestion and absorption of WG may result in a reduction in postprandial glucose and insulin response, which may, in turn, favor the oxidation and lipolysis of fat rather than its storage. In contrast, evidence from clinical studies supports that diets rich in highly digestible carbohydrates, indicative of greater refined grain or low fiber intake, can alter lipoprotein secretion and clearance, leading to higher fasting triglyceride concentrations.
  • Fermentation of dietary fiber by the microbiota present in the colon produces short-chain fatty acids (SCFAs), which are involved in lipid metabolism and satiety and glucose metabolism.
  • Other nutritional attributes of WG, such as magnesium, potassium, selenium, and zinc, as well as antioxidants and polyphenols, may contribute to lowering blood pressure and improving glucose and insulin metabolism.

The starch-rich diet our ancestors ate had to be less refined. No?  And it benefited them. They did cook though, which is a type of food processing. Imagine the fiber in that diet!

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