What does "Eat more whole grains" really mean?
Sunday, September 26, 2010
LifeTime WeightLoss in Carbohydrates, Nutrition, carbs, dietary recommendations, whole grains

Written by Tom Nikkola - Director of Nutrition & Weight Management

Each weekend when my wife and I do our grocery shopping, we have a habit of walking through the aisles and paying attention to the claims made on many of the packaged foods. Many of the foods seem to have a claim regarding whole grains, such as “High in whole grains,” “Contains ‘x’ grams whole grains” or something similar. Unfortunately, many people will assume that anything called out on a label must be healthy. Many of these claims can be found on highly processed, high-carbohydrate foods such as breakfast cereals. Besides the packages on food in the store, “eat more whole grains” is a common recommendation from “experts” on television, in magazines and on the internet. If you’re ready to make a change to your diet, hopefully this will help clarify some misconceptions when it comes to the amount of whole grains in your diet.

Suggested Benefits of Whole Grains

There have been many observational studies done on whole grains, which seem to suggest that whole grain consumption plays an important role in weight management, heart health and other health benefits. Observational studies look at large populations of people and compare certain habits. In this case, they may compare the occurrence of health problems (i.e. obesity, CVD, etc.) and amount of whole grains consumed. Observational studies only show associations. Many of them have found that those who eat more whole grains are healthier.

In a large population study, associations between colorectal cancer and whole grain intake were reviewed. It found, in men, higher whole grain intake was associated with lower risk of colorectal cancer. However, the reduced risk was only associated with whole grain bread. In women, there wasn’t a difference. This is another study that can’t show whole grains reduces colorectal cancer risk; only that there is an association. It’s possible the men who chose to eat whole grain breads also followed other healthy lifestyle factors which would reduce the risk of the cancer. Other studies of populations have shown similar associations between health and whole grain intake, but they only show associations.(1)

Another study design for whole grains has been to compare consumption of a certain amount of whole grains with eating refined grains. Researcher tested the occurrence of cardiovascular risk by using a controlled trial in which one group consumed refined grains and the other group consumed three servings of whole grains each day. Those who were in the whole grain group had reduced markers of cardiovascular risk, but that would be expected when comparing to another group eating refined grains. The conclusion from the researchers was “Daily consumption of 3 portions of whole-grain foods can significantly reduce cardiovascular disease risk in middle-aged people mainly through blood pressure-lowering mechanisms. The observed decrease in systolic blood pressure could decrease the incidence of coronary artery disease and stroke by  15% and 25%, respectively.” Unfortunately, most people may be misled into thinking adding three servings of whole grains to their diet will improve their cardiovascular risk, but that is not what the study suggests. It only suggests replacing refined grains with whole grains may improve heart health.

A study published in the British Journal of Nutrition studied a group of over 300 people who either stayed on their normal diet, or had three servings (60 grams) of whole grains added to their diet. There was no improvement in cardiovascular disease risk in the whole grain group, leaving the researchers to conclude “The lack of impact of increasing WG (whole grain) consumption on CVD risk markers implies that public health messages may need to be clarified to consider the source of WG and/or other diet and lifestyle factors linked to the benefits of whole-grain consumption seen in observational studies.”(2) This is different than the study in the previous paragraph in that people weren’t intentionally put on a refined grain diet and compared to another group on whole grains. Since one group maintained their normal diet and the other added whole grains, this study more closely resembles how most people make changes to their diet when they increase whole grains to improve their health. They go from their normal diet and add a few servings of whole grains, which appears to not have a positive effect on heart health after all. The same study design was used in another study with similar results.(3) This study design would be like putting people on diets that added either three servings of potato chips or three servings of potatoes, and saying whole potatoes improve health. Who would argue that? Yet, most people would know not to simply add three servings of potatoes to their diet if they didn’t need to eat the calories.

What about whole grains and weight loss? A study published in 2008 showed no difference between those eating more whole grains compared to those eating refined grains for weight loss. However, those who were eating whole grains did have a greater decrease in percentage body fat and a greater decrease in visceral fat. Again, this would be expected when you compare refined grains, which raise blood-sugar levels faster, with whole grains.(4) Another study attempted to show consuming more cereal grains helps with weight loss, but again, this was another population study. All it could show was that people who weigh less tend to eat more whole grains. They may also be the type of people who eat less fast food, exercise more and live a healthier lifestyle. Unfortunately, population studies are not designed to find the specific cause of the health benefit. Their findings are often exaggerated.(5)

Whole Grains and Other Foods

Based on the above studies, it appears eating whole grains can be better than eating refined grains, but does that mean they’re optimal carbohydrate sources? Not at all. Most whole grain foods contain gluten, which is related to many diseases. Other starchy carbohydrates such as sweet potatoes, yams, gluten-free oatmeal and rice provide carbohydrates and micronutrients without the negatives of the gluten-containing grains. Of course, for most of us who are pretty sedentary, the carbohydrates we eat from non-starchy vegetables and fruit provide most of the carbohydrate we need in our diet.

Summary

There’s no doubt that most Americans eat far too much processed food, especially processed carbohydrates. Refined grains are devoid of their natural fiber and nutrients that help our bodies digest them and help us manage weight. Gluten-free starchy carbohydrates can play a more important part of a healthy diet when they are consumed in moderation, in amounts relative to people’s level of activity. Eating just enough starchy carbohydrates to complement an individual’s level of activity is a step in the right direction toward optimal health. The next time you see an ad claiming “eat more whole grains,” ask yourself where the advice is coming from. It’s possible studies may show more benefits in the future, but to date, the main benefits of whole grains seem to be in using them to replace refined carbohydrates. So, to answer the question in the title, eat more whole grains in place of refined grains, but remember that there are healthier carbohydrate sources than many of the whole grain options most people think of.

For a fantastic review of the healthiest foods to eat, including your best sources of carbohydrates, check out Jonny Bowden’s book The 150 Healthiest Foods on Earth. Also, if you haven't had a chance to yet, be sure to download our new E-Book, Eat Well. Live Well.

References:

  1. Brownlee I, Moore C, Chatfield M, et al. Markers of cardiovascular risk are not changed by increased whole-grain intake: the WHOLEheart study, a randomized, controlled dietary interventionBrit J Clin Nutr. 2010;104:125-134.
    Egeberg R, Olsen A, Loft S, et al. Intake of wholegrain products and risk of colorectal cancers in the Diet, Cancer and Health corhort study. Brit J Canc. 2010;103:730-734
  2. Tighe P, Duthie G, Vaughan N. Effect of increased consumption of whole-grain foods on blood pressure and other cardiovascular risk markers in healthy middle-aged persons: a randomised controlled trial. Am J Clin Nutr. 2010;92:733-740
  3. Glacco R, Clemente G, Cipriano D, et al. Effects of the regular consumption of wholemeal wheat foods on cardiovascular risk factors in healthy people. NMCD. 2010;20(3):186-194
    Katcher HI, Legro RS, Kunselman AR, et al. The effects of a whole grain-enriched hypocaloric diet on cardiovascular disease risk factors in men and women with metabolic syndrome. Am J Clin Nutr. 2008;87(1):79-90
    McKeown N, Yoshida M, Shea MK, et al. Whole-Grain Intake and Cereal Fiber Are Associated with Lower Abdominal Adiposity in Older Adults. J Nutr. 2009;139(10):1950-1955

This article is not intended for the treatment or prevention of   disease, nor as a substitute for medical treatment, nor as an   alternative to medical advice. Use of recommendations in this and other   articles is at the choice and risk of the reader.

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