Grains and Legumes: Any Effect on Heart Disease and Stroke?

Several scientific studies published in the first five years of this century suggest that whole grain consumption protects agains coronary heart disease and possibly other types of cardiovascular disease, such as stroke. 

Note that researchers in this field, especially outside the U.S., use the term “cereal” to mean “a grass such as wheat, oats, or corn, the starchy grains of which are used as food.”  They also refer frequently to glycemic index and glycemic load, spelled “glycaemic” outside the U.S.  Most of the pertinent studies are observational (aka epidmiologic): groups of people were surveyed on food consumption, then rates of diseases were associated with various food types and amounts.  “Association” is not proof of causation. 

Here are highlights from a 2006 review article in the European Journal of Clinical Nutrition

The researchers concluded that a relationship between whole grain intake and coronary heart disease is seen with at least a 20% and perhaps a 40% reduction in risk for those who eat whole grain food habitually vs those who eat them rarely.

Whole grain products have strong antioxidant activity and contain phytoestrogens, but there is insufficient evidence to determine whether this is beneficial in coronary heart disease prevention.

Countering the positive evidence for whole grain and legume intake has been the Nurses Health Study in 2000 that showed women who were overweight or obese consuming a high glycaemic load (GL) diet doubled their relative risk of coronary heart disease compared with those consuming a low GL diet.

The intake of high GI carbohydrates (from both grain and non-grain sources) in large amounts is associatied with an increased risk of heart disease in overweight and obese women even when fiber intake is high but this requires further confirmation in normal-weight women.

Promotion of carbohydrate foods should befocused on whole grain cereals because these have proven to be associatied with health benefits.

Whether adding bran to refined carbohydrate foods can improve the situation is also not clear, and it was found that added bran lowered heart disease risk in men by 30%.

Recommendation:  Carbohydrate-rich foods should be whole grain and if theyare not, then the lowest GI product available should be consumed.

My Comments

This journal article focuses on whole grains rather than legumes, and promotes whole grains more than legumes.  For people with diabetes, this may be a bit of a problem since grains—whole or not—generally have a higher glycemic index than legumes, which may have adverse effects on blood sugar control.  Keep in mind that highly refined grain products, like white bread, have a higher glycemic index than whole grain versions.

Did you notice that the abstract doesn’t recommend a specific amount of whole grains for the general population?  My educated guess would be one or two servings a day. 

Grains are high in carbohydrate, so anyone on a low-carb diet may have to cut carbs elsewhere. 

Diabetes predisoses to development of coronary heart disease.  Whole grains seem to help prevent heart disease, yet may adversely affect glucose control, contributing to diabetic complications.  It’s a quandary.  “Caught between the horns of a dilemma,” you might say.  So, what should a diabetic do with this information in 2010, while we await additional research results?

Several options come to mind:

  1. Eat whatever you want and forget about it.
  2. Note whether coronary heart disease runs in your family.  If so, try to incorporate one or two servings of whole grains daily, noting and addressing effects on your blood sugar.
  3. Try to eat one or two servings of whole grains a day, noting and addressing effects on your blood sugar.  Then decide if it’s worth it.  Is there any effect?  Do you have to increase your diabetic drug dosages or add a new drug?  Are you tolerating the drugs?    
  4. Assess all your risk factors for developing heart disease: smoking, sedentary lifestyle, high blood pressure, age, high LDL cholesterol, family history, etc.  If you have multiple risk factors, see Option #3.  And modify the risk factors under your control.   
  5. Get your personal physician’s advice.    

Before you stress out over this, be aware that we don’t really know whether a diabetic who doesn’t eat grains will have a longer healthier life by starting a daily whole grain habit.  Maybe . . . maybe not.  The study hasn’t been done.    

Steve Parker, M.D.


Flight, I. and Clifton, P.  Cereal grains and legumes in the prevention of coronary heart disease and stroke: a review of the literatureEuropean Journal of Clinical Nutrition, 60 (2006): 1,145-1,159.

Malik, V. and Hu, Frank.  Dietary prevention of atherosclerosis: go with whole grainsAmerican Journal of Clinical Nutrition, 85 (2007): 1,444-1,445.


Filed under Carbohydrate, coronary heart disease, Diabetes Complications, Grains, legumes, Stroke

4 responses to “Grains and Legumes: Any Effect on Heart Disease and Stroke?

  1. Vivian

    What I would like to know about those studies: are they measuring the whole grain ‘eaters’ against those who are eating refined grain only, or those who are eating no grain at all? I think the answer makes a huge difference.

    As a T2 diabetic, who measured her blood sugar fasting, then 1 and 2 hours after each meal for many months, eliminating foods that pushed my blood sugar out of an acceptable range, I found I had to eliminate all grains from my diet, whole or otherwise. Even oatmeal without any sweet topping, just with milk, pushed my blood sugar to an unacceptable level. Legumes have the same effect.

    Whole non-starchy vegetables and berries and some other fruits did not have the same impact on my blood sugar.

    So, I’ve eaten no grains for 3 years , nor legumes (nor any processed foods, or very starchy vegetables or simple sugars) and have maintained normal blood sugar levels, without medication.

    Am I healthier in the long run having eliminated all grain and maintaining normal blood sugars ‘naturally’? I sure hope so. What I do know is that I’ve never felt healthier.

    • Hi, Vivian.

      It’s hard to improve on “I’ve never felt healthier”!

      Most of the epidemiological studies compare consumption of whole grains versus refined grains, and grain eaters vs low- or no-grain eaters. There’s quite a bit of variability. Your experience with grains is not uncommon in people with diabetes.


  2. nigeepoo


    At the moment, manufacturers are allowed to call their products “whole grain” if everything that was in the grain is in their products.

    However, if I have my car crushed into a cube, it’s still technically a “whole car”, but its function has changed (& not for the better!). Ditto for paper money that’s been put through a shredder. A bag full of shredded whole £50 notes is worthless.

    To me, if it doesn’t look like a whole grain, it ain’t a whole grain! So rolled wheat & oat flakes are whole (even though they’ve been squashed flat), puffed wheat/rice are whole and rice/corn/quinoa etc are whole but anything else isn’t.


  3. Hi, Nige. Thanks for commenting. Darya Pino at her blog SummerTomato writes about that issue, too. She prefers the term “intact grains” over whole grains. She thinks the intact grains are healthier than pulverized grains. To the extent that lower glycemic index may be important, intact grains would prevail over pulverized.

    I bet, however, the population surveys that associate health benefits with whole grains simply queried about whole versus refined grains, not using the term “intact.”