The Great Grain Debate

One of the biggest controversies regarding carbohydrates lies within the power of grains. Are they good for you, or are they bad for you? The great debate divides the opponents into opposite sides, from the paleo community to the flexible dieting community. Both stand their ground, picking and choosing their scientific evidence based on their opinions. This is where our answer lies, for science never lies. With “Gluten Free”, “Grain free”, and “Wheat Free” labels continuing to line the shelves in supermarkets, consumers are posed to question if these ingredients are ones to fear, or love. We must be able to distinguish what these labels mean, as well as understand how grains effect our health, performance, and physique goals. By digging into the literature, we can help dissipate the controversy and spread the scientific truth, that grains are glorious. When implemented in the right types and amounts, they can be an important part of a well- balanced diet.

One of the key contributing factors to the confusion of the grain lies in the fallacy of composition. The fallacy of composition occurs when one infers that something is true of a whole, when in fact it is true of some part of a whole. In the case of the grain, the entire grain is either misjudged as good or bad, and the grain is not looked at for its different components. Grains are categorized into 2 different types, whole grains or refined grains. Whole grains contain the entire grain kernel, which includes the bran, germ, and endosperm. The germ is responsible for most nutrients, phytochemicals, and healthy fats, while the bran is an excellent source of fiber, B-vitamins, and minerals. Whole grain examples include oatmeal, brown rice, whole-wheat flour, whole-wheat breads, popcorn, and bulgur. Refined grains are ones in which the bran and germ have been removed through milling. This process not only alters the grains nutrient profile, but changes its effects on blood glucose and digestion within the body. Many refined grains are enriched with various vitamins and minerals to either add back the nutrients lost in milling, or add additional nutritional benefit to the product. Examples of refined grains include refined breakfast cereals, white breads, white flours, white rice, and many desserts and pastries.

Whole wheat and refined grains metabolize quite differently in the body and their digestion is also influenced by a meal’s total dietary components. For example, the fiber within the bran of whole grains helps to slow the digestion of starch into glucose, helping to maintain a steady blood sugar levels upon consumption. The fiber also helps to lower blood cholesterol and remove waste within the digestive tract, including excreting excess estrogen in the body. Refined grains tend to have less fiber and digest and spike blood glucose at a faster rate, which causes issues for individuals who struggle with blood sugar control or insulin resistance. When digested along with a fat source however, the fat works to slow digestion and helps to stabilize blood sugar levels. Many individuals will try and stay away from refined grains due to their ability to spike blood sugar levels and insulin, but people tend to forget that they must look at the big picture, which is the full meal eaten. When looking at the response on blood glucose and insulin, every component in the meal must be considered since digestion and absorption can change based on a meal’s full composition. Just spiking insulin as well is not a fate for fat gain, for it triggers the uptake of nutrients into the muscle and allows for growth and repair to occur. Insulin is stimulated by both carbohydrates and proteins and serves as a light switch for our bodies to turn from catabolism to anabolism, storing glucose into our tissues for storage and future use.

A case against grains lies in insulin resistance, food allergies, and inflammation. In insulin resistance, one’s body is not able to lower its blood sugar in response to spikes in insulin from a meal. This is because the beta cells in the pancreas are not able to keep up with the increased demand for insulin, causing the glucose that would normally be shuttled to liver or muscle tissue to stay within the bloodstream. Unless there is sufficient insulin to lower blood glucose back to normal, these levels remain elevated. This continues a cycle of high blood sugar, weight gain, and can contribute to diseases such as PCOS (Polycystic ovarian syndrome), Type 2 diabetes, and metabolic syndrome. To avoid insulin resistance and enhance insulin sensitivity, one should consume a balance of healthy, whole grains, avoid constant spiking of insulin, and focus on lifestyle and exercise techniques such as incorporating resistance training and HIIT cardio in order to enhance insulin sensitivity. It is not the grain itself that causes insulin resistance but a variety of genetic, lifestyle, and overall dietary factors. Maintaining a healthy body weight, exercising with resistance training, and getting proper sleep are important steps to lower your risk for insulin resistance and improving your overall health.

Grains have also recently been perpetuated as a “cause of inflammation”, which is seen in the recent expansion of the gluten free craze and the paleo diet. Though some grains may cause inflammation, it should be noted that for most individuals, this occurs due to dietary allergies, intolerance, or improper digestion and that inflammation is mostly seen with the intake of too many refined grains. A gluten free diet is essential for individuals with Celiac Disease, in which the consumption of the protein, gluten, from grains causes an immune attack on their intestinal cells, leading to pain, intestinal damage, and various health effects. For someone with an unconfirmed allergy, disease, or intolerance, avoiding gluten is unnecessary and can even lead to nutritional deficiencies, create intolerances, and can even spell trouble for weight loss. Many gluten free foods contain higher calories and carbohydrates, with less nutrients and fiber than their gluten containing counterparts. Just because something is gluten free does not make it a healthier alternative or mean that it is lower in calories. It simply means that the protein gluten is not there. A gluten free diet should be implemented for medical reasons, and if one is trying to reduce inflammation, they should focus on reducing refined grains, not avoiding the grain or gluten altogether. Various studies show that refined grains high in sugar can contribute to inflammation, so limiting products such as breakfast cereals, fruit snacks, fruit juices, and many convenience packaged snacks can help to reduce the risk of inflammation and help one focus on consuming carbohydrates with more nutritional calories.

Looking at the benefits of the grain, whole grains consistently provide evidence for helping with weight loss, reducing the risk of chronic disease, and helping to maintain a healthy digestive system. In a meta-analysis from the journal Circulation, it was found that people who ate 70g/day of whole grains vs little to no whole grains had a 22% lower risk of mortality, 23% lower risk for cardiovascular disease, and 20% lower risk for cancer mortality. Annals of Epidemiology also established a large prospective study with over 72,000 postmenopausal women without diabetes and found a 43% reduction in women with the highest whole grain intake compared to those with little to no whole grain intake. Looking at the effects of whole grains on gut microflora, The American Journal of Clinical Nutrition concluded that diets rich in whole grains compared to refined grains lead to modest improvements in health gut microbiota and certain immune responses. Another tightly controlled study in this journal assessed the direct difference of whole grains vs. refined grains on metabolic rate and weight loss. They found that the whole grain group lost close to 100 calories a day extra due to a combination of fecal loss and increased resting metabolic rate. However, it should be noted that all studies have limitations and that physical activity was not tightly controlled, which could play a major role in the results. Regardless, there continues to be emerging evidence in the literature praising the benefits of the whole grain. There is no doubt that it’s addition can help to increase satiety, dietary adherence, and play key roles in healthy cholesterol and blood glucose levels.

Our great grain debate comes down to the answer of individual needs and variability. One should make sure to consume an overall healthy, balanced diet and limit potential foods, including grains, that trigger individualized allergies, inflammation, and immune responses. An easy suggestion for your diet is to consume at least half of your carbohydrates as whole grains, and if looking to maximize insulin sensitivity, to consume your simple, quick digesting carbohydrates around your workout times. When looking to choose a whole-grain product, one should focus on choosing grains high in fiber, vitamins, and minerals in order to get the most bang for your buck and to consume them within daily caloric needs. The great grain debate tends to be “go grains!” or “no grains!”. Instead of focusing on limiting grains, the focus should be on overall carbohydrate quality in the diet. Whether your goal is fat loss or gaining muscle, incorporating grains into your daily diet in the right types and amounts can help you to reach your fitness and physique goals while helping you to live a long, fulfilled and healthy life.

References:
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Parker ED, Liu S, Van Horn L, et al. The association of whole grain consumption with incident type 2 diabetes: the Women’s Health Initiative Observational Study. Ann Epidemiol. 2013;23:321-7.

Roberts, S. B., Karl, J. P., Meydani, M., Junaidah B. B., Vanegas, S. M., Goldin, B., Kane, A., Rasmussen, H., Saltzman, E., Vangay, P., Knights, D., Chen, C-Y. O., Das, S.K., Jonnalagadda, S.S., Meydani, S.N.. (2017). Substituting whole grains for refined grains in 6-week randomized trial favorably affects energy balance parameters in healthy men and post-menopausal women. American Journal of Clinical Nutrition.

Saturni L, Ferretti G, Bacchetti T. The Gluten-Free Diet: Safety and Nutritional Quality. Nutrients. 2010;2(1)16-34.

Vanegas, SM, et al. Substituting whole grains for refined grains in a 6-wk randomized trial has a modest effect on gut microbiota and immune and inflammatory markers of healthy adults. The American Journal of Clinical Nutrition, 2017; ajcn146928 DOI: 10.3945/ajcn.116.146928

“Whole Grains.” The Nutrition Source. Harvard School of Public Health. 30 May 2017. Web. Accessed 07 July 2017.

Zong G, Gao A, Hu FB, Sun Q. Whole Grain Intake and Mortality From All Causes, Cardiovascular Disease, and Cancer: A Meta-Analysis of Prospective Cohort Studies. Circulation. 2016;133:2370-80.