In a recent article published by Live Science, Sara Miller claims that three or more servings of whole grains each day is linked to longer life, and substantially decreased risk of death from heart disease, cancer, and any cause in general.  Although I do not necessarily disagree with the value of whole grains, there are many flaws and missing pieces in this article.

Where did this information come from?

The information comes from reports of people included in 14 different studies, ranging from 6-10 years in length.  The meta-analysis included 786,000 people, and 98,000 died.  23,000 of these deaths occurred due to heart disease, and 37,000 occurred from cancer.  These causes of death happen to be the leading cause of death in general, and to correlate them with lack of whole grains is not necessarily valid.  Ichim, Patel and Shafer state that cardiovascular disease (CVD) is “a leading cause of morbidity and mortality worldwide” (2016).

Of the reports of those who ate 3 or more servings of whole grains in a day, 70% of those whole grain sources came from bread and cereal grains.  These foods are highly processed and packaged foods that would have claims of being whole grains on the box.  It is then possible, that those who look for buzz words such as “whole grain” are also more health conscious in other aspects of their life such as exercise, and other health conscious dietary choices.

Other claims in this article state that whole grains are associated with lower blood sugar levels, cholesterol levels and body fat percentage.  Although the wording is somewhat ambiguous, it is safe to assume they are comparing those who eat three or more whole grain servings per day to those who eat one or less.  I would agree that compared to refined grains, whole grains will have less of an effect on blood sugar, assist in carrying excess cholesterol out of the body, and store less fat.  However, if you compare whole grains to vegetables, and high quality organic protein and fat sources, the latter sources will have even less of an effect on blood sugar, and fat storage. Cholesterol does have the ability to be carried out of the body with the help of fibre, but there are many ways to incorporate fibre into the diet.

Thinking critically.  What’s missing?

The main flaw in this article is that it fails to take any confounding variables into consideration.  There are many things that contribute to CVD and cancer other than the absence of whole grains such as stress, lack of sleep, environmental toxins, age and health of participants and other health issues such as sugar intake, alcohol intake and tobacco intake, and exercise to name a few.  So although whole grains may be a valuable part of a healthy diet,  there are too many contributing factors to heart disease, cancer, and death in general, that it is not valid to connect whole grains to these deaths without controlling for confounding variables.

The most obvious confounding variable that may have a pronounced effect on incidence of heart disease and cancer is exercise.  Kirkham & Davis (2015) conducted a review on exercise and its effects on breast cancer survivors and their risk of CVD to see if exercise could be of some benefit for preventing CVD in this population.  They found that “aerobic exercise training and other forms of physical activity are effective in primary and secondary prevention of cardiovascular disease.” and that “exercise can favourably improve a number of cardiovascular risk factors including hypertension, raised cholesterol/lipids, overweight and obesity, raised blood glucose or diabetes and cardiorespiratory fitness” (Kirkham & Davis, 2015).  This is just one example of the many confounding variables that can have a positive effect on characteristics and symptoms that lead to CVD and cancer, increased cholesterol, blood sugar and body fat percentages.

There is also some research on different diets where grains are less prevalent in the diet.  The Palaeolithic diet is void of all grains.  In a 2 week long RCT single-blinded pilot study on the effects of a paleolithic diet on subjects with 2 or more characteristics of metabolic syndrome (large waist circumference, elevated triglycerides, reduced HDL, high BP, elevated fasting blood glucose).  Subjects were controlled for exercise routines and instructed to continue with current routines, if any.  The control group was given a healthy diet according to the Dutch Health Council.  They found that characteristics of metabolic syndrome were decreasing, and so was body weight despite efforts to maintain it, on the Paleo Diet (Boers et al., 2014).   So although certain unprocessed whole grains may be beneficial to health, they hardly seem responsible for the decrease in death related to CVD and cancer, as characteristics of metabolic syndrome, are also precursors to diseases such as CVD and cancer.  Furthermore, the Paleo Diet in this study had a direct lowering effect on cholesterol, blood sugar, and body fat!

An interesting look at the importance of the health and bacterial balance in the intestines was also studied.  Ichim et al. conducted a study using DBR, a probiotic and digestive enzyme supplement, and found that it lowered LDL cholesterol, increased HDL cholesterol in mice and in vitro.  They found that “lactic acid bacteria are capable of modulating hypercholesterolemia” and that “daily consumption of probiotic products [is] one strategy for addressing hypercholesterolemia in patients at risk of afflicted with cardiovascular disease” (2016).  The health of the microbiome is crucial to overall health, and just so turns out to have a specific effect on characteristics and symptoms leading to CVD. 

In Conclusion

There is not one single approach to diet and lifestyle that will prevent cardiovascular disease and cancer.  It is clear that many factors have an effect on one’s health.  The addition or removal of whole grains in a diet may be beneficial or not to any given person, but on a large scale, there are many general health practices that can assist in decreasing risk of disease.  These include physical activity in any form, stress management, adequate, sleep, hydration and nutrients in the diet.  Furthermore, there is no optimal diet for the entire population.  Figuring out what your body needs and doesn’t need is a personal endeavour.  There are populations who have thrived on many different diets that include or don’t include grains.  What is most important is that the foods in the diet are whole foods and that they are free of harmful additives and processing.

References

Boers, I., Muskiet, F.AJ., Berkelaar, E., Schut, E., Penders, R., Hoenderdos, K., Wichers, H.J., &  Jong, M.C. (2014).  Favourable effects of consuming a Palaeolithic-type diet on characteristics of the metabolic syndrome: a randomized controlled pilot-study.  Lipids in Health and Disease, 13:160. doi: 10.1186/1476-511X-13-160

Ichim, T.E., Patel, & A.N., Shafer, K.A. (2016).  Experimental support for the effects of a probiotic/digestive enzyme supplement on serum cholesterol concentrations and the intestinal microbiome.  Journal of Translational Medicine, 14:184. doi: 10.1186 s12967-016-0945-2

Kirkham, A.A., & Davis, M.K. (2014). Review Article: Exercise Prevention of Cardiovascular Disease in Breast Cancer Survivors.  Journal of Oncology, 2015. doi: 10.1155/2015/917606