Cut your risk of heart disease with whole grains

ere at Health meets Food we've written extensively about the power of whole grains - after all, whole grains are one of the 9 principles of the Mediterranean Diet. Not only are they more satisfying due to their higher fiber content, we've seen that diets rich in whole grains can help you lose more abdominal fat, help older people reduce their overall risk of metabolic syndrome, improve people's insulin response (without losing weight), and help you avoid heart disease as well as Type 2 diabetes.

Many of those previous studies were cross-sectional (looking at a specific moment in time), longitudinal (tracking people for an extended period), or involved providing whole grain foods to be added to the participants' usual diets. In a very rigorous study, authors affiliated with the Cleveland Clinic decided to provide the entirety of their participants' diets (both food and drink) in a crossover study designed to assess the impact of whole grains on weight and body fat, blood pressures, cholesterol scores, and insulin scores (J Nutr 2016;146(11):2244-51).

Thirty-three overweight or obese men and women of at least 50 years of age, with no history of heart disease, participated in the study. For the first 8 weeks half of the participants were provided a balanced diet designed to maintain their body weight while including mostly refined grains, while the other half of the participants were provided a similarly balanced and body-weight-maintaining diet that included mostly whole grains.

After the initial 8 weeks the participants returned to their usual diets for 10 weeks for what is known as a "washout period." For the 8 weeks following the washout period, the two groups switched their prescribed diets so that the group that had initially received mostly refined grains for the first 8 weeks received whole grains for the second 8 weeks and vice versa.

At the start and end of each test diet period the authors recorded the participants' weight and tested their blood pressures along with other blood tests, including cholesterol and glucose scores.

It's interesting that both groups lost about the same amount of weight and fat mass during the two testing periods of the study, while also cutting total cholesterol and LDL cholesterol. The big difference in results between the two diet periods was in diastolic blood pressures (DBP) (the bottom number in a blood pressure score): the refined grains diet reduced DBP by about 1% while the whole grains diet reduced DBP by about 8% - which is about a 10% improvement in overall blood pressures.

What this means for you

We physicians don't talk much about diastolic blood pressures specifically, but you should know that every ten-point increase in diastolic blood pressure doubles your risk of death from heart disease or stroke. Keep your blood pressure - both scores - in the normal range by reducing your sodium intake (here are 3 Easy Steps to a Low Sodium Diet) and switching to whole grains rather than refined grains. Here are some easy ways to make the switch.

First posted: February 1, 2017