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If whole grains aren’t part of your daily diet, they should be.
Observational studies have consistently linked higher intake of whole grains to lower risks of coronary heart disease, stroke, Type 2 diabetes, hypertension, certain cancers and premature death.
It’s less clear, however, whether whole grains improve the risk factors that contribute to those chronic diseases, such as elevated LDL (bad) cholesterol, high blood pressure and insulin resistance.
But now a new meta-analysis of randomized controlled trials – the largest and most comprehensive review to date – offers the strongest evidence yet that higher whole-grain intake is tied to improvements in many cardiometabolic risk factors. What’s more, the study revealed the amount of whole grain associated with the greatest improvements in these health markers.
Here’s a breakdown of the study and its findings, plus simple ways to add more whole grains to your daily menu.
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Whole grains 101
Cereal grains, such as wheat, rye, barley, rice and oats, start out as whole-grain kernels that contain three parts: the fibre-rich outer bran layer, the nutrient-dense germ and the starchy endosperm.
When grains are refined, the bran and germ are removed, stripping away most of the fibre, about one-quarter of the protein and many other nutrients.
Whole grains, on the other hand, retain all three parts in their original proportions, whether they’re eaten as whole kernels, cracked or flaked kernels, rolled oats or whole-grain flour.
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The latest research
For the study, published Sept. 15 in the European Heart Journal, researchers set out to determine the effects of whole-grain intake on a wide range of cardiometabolic risk factors.
To do so, they reviewed 87 randomized controlled trials conducted across Asia, Europe, Canada, the U.S., Australia and Brazil involving 6,529 adults. Unlike previous reviews, they also looked at how much whole grain people needed to eat in order to gain the largest improvements in cardiometabolic risk factors.
The results showed that higher whole-grain intake was associated with a lower body weight, smaller waist circumference, reduced blood pressure, improved insulin sensitivity and lower levels of cholesterol, triglycerides, blood glucose and interleukin-6, an inflammation marker in the bloodstream.
The evidence was strongest for reductions in total cholesterol, body weight, waist circumference and interleukin-6. It was reasonably strong for improvements in LDL cholesterol, HDL (good) cholesterol, triglycerides, blood pressure, fasting glucose, hemoglobin A1C, fasting insulin and body fat percentage.
For most risk factors, the largest improvements were observed at a whole-grain intake of roughly four to six servings a day.
One serving of whole grains is equivalent to one half-cup of cooked whole-grain rice (brown, red, black), quinoa, farro, freekeh, bulgur, oatmeal or whole-grain pasta, one slice of 100-per-cent whole-grain bread, one mini (one ounce) 100-per-cent whole grain muffin or one cup of 100-per-cent whole-grain, ready-to-eat cereal.
Although the improvement in each individual risk factor was modest, the researchers wrote that improving several risk factors at the same time could translate into greater protection against heart disease and stroke over the long term.
According to an editorial that accompanied the study, the new study strengthens the case that whole grains themselves directly contribute to better cardiometabolic health because it found consistent benefits across multiple risk factors.
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How whole grains may protect cardiometabolic health
Whole grains are rich in fibre, vitamins, minerals and bioactive plant compounds.
Researchers believe they support cardiometabolic health by improving insulin sensitivity, reducing inflammation, nourishing beneficial gut bacteria and promoting satiety.
Together, these effects can lead to healthier cholesterol, blood pressure, blood sugar and body weight.
Easy ways to eat more whole grains
The key message from the new study is simple: Replace refined grains with minimally processed whole grains.
Batch cook whole grains to have them on hand to quickly add to meals. Cooked whole grains will keep for three to four days in the fridge and two to three months in the freezer.
Toss cooked bulgur or farro into green salads or over roasted vegetables. Stir cooked barley, red rice, black rice or spelt berries into soups, stews and chilis. Make whole-grain bowls with quinoa or brown rice.
Stuff burritos, bell peppers and cabbage rolls with whole-grain rice, farro or barley instead of white rice.
Swap refined pasta for whole-wheat pasta. Its nutty flavour works well in a robust marinara or puttanesca sauce (my favourite).
Branch out from oatmeal to add a variety of whole grains to breakfast. Try whole-grain hot cereal blends such as Arva Flour Mills Red River (cracked wheat, cracked rye, whole flaxseeds), Rogers Ancient Grain Blend (oats, barley flakes, rye flakes, spelt flakes, kamut flakes, millet, quinoa) or one of Bob’s Red Mill multigrain hot cereals blends.
Read labels on packages of whole-grain breads, crackers and breakfast cereals. If you don’t see a statement of “100-per-cent whole grain,” scan the ingredient list to make sure the product doesn’t contain refined grains (for example, wheat flour).
Leslie Beck, a Toronto-based private practice dietitian, is director of food and nutrition at Medcan.