SEARCH HEALTH STUDIES

Avoiding Wheat Linked with Low Fiber, High Saturated Fat Intakes

Although wheat has been a staple crop for centuries, in recent years it has (unjustly) become a scapegoat by fad-dieters seeking a wheat-free or low-carb diet. In this study, researchers analyzed the diets of 30 people who reported avoiding wheat to see if this wheat-free diet impacted their nutrient intake. The wheat avoiders (many of whom happened to be avoiding dairy as well) consumed too little fiber and calcium, and too much saturated fat and total fat according to dietary recommendations. Interestingly, although 85% of the participants reported avoiding ALL wheat products, ⅓ of the participants reported eating a wheat-based food in their food record (mostly in the form of discretionary snacks/desserts).
Nutrition & Dietetics: The Journal of the Dietitians Association of Australia. 2019 Jul;76(3):305-312. doi: 10.1111/1747-0080.12521. (Golly S et al.)

Low-Carb Paleo Diet Linked with Unhealthy Changes to Gut Microbiome

Paleo diets tend to be high in meat and vegetables, while restricting all grains and dairy products. In this study, researchers analyzed the microbiome of 44 people who had been following a Paleo diet for at least 1 year, and 47 people who eat a healthy diet reflective of dietary guidelines. Those strictly following a Paleo Diet and those eating a standard healthy diet ate significantly more fiber than those only loosely following a Paleo diet. However, those who strictly followed the Paleo diet (eating the lowest levels of whole grains and total grains) were significantly more likely to have higher levels of TMAO (a compound generated by the gut microbiome that is associated with plaque buildup in the arteries). The authors also added that “the rationale to exclude whole grains is not supported by data presented here; being inversely associated with body weight and TMAO concentrations.”
European Journal of Nutrition. 2019 Jul 5. doi: 10.1007/s00394-019-02036-y. [Epub ahead of print] (Genoni A et al.)

Gluten-Free Diet Not Appropriate without Medical Diagnosis

Gluten is a compound found naturally in wheat, barley, and rye that helps dough stretch and bread rise. Many misguided dieters today choose to go gluten-free, even though only about 1% of the population has celiac disease (an autoimmune disorder where gluten must be avoided). In this review, researchers analyzed studies on the nutritional adequacy of gluten-free diets. They found that gluten-free diets tend to have less fiber, calcium, magnesium, zinc, vitamin B12, folate, and vitamin D, and tend to have more saturated fat and exposure to arsenic. The researchers note that “the majority of persons adopting a [gluten-free diet] have no medical basis for doing so,” and that “only persons with [celiac disease], [wheat allergy], or [non celiac gluten-sensitivity] should follow a [gluten-free diet], and they should do so under medical supervision.”
Journal of Nutrition and Metabolism. 2019 Jul 1;2019:2438934. doi: 10.1155/2019/2438934. [Diez-Sampedro A et al.]

Whole Grains Linked with Healthy Aging

Longevity is fascinating to study, but what is perhaps more important than the years in your life is the life in your years – the ability to age successfully from a medical, social, and lifestyle point of view. In this study, researchers evaluated whole grain intake and measured “successful aging” (using social, lifestyle, and medical indicators) in a group of 3,349 adults ages 50+. Those eating the most whole grains (about 7 servings per day) were significantly more likely to score higher on the “successful aging index” than those eating the least whole grains (about 1.5 servings per day). Those eating the most whole grains were also less likely to have high blood pressure, diabetes, and high cholesterol.
Nutrients. 2019 May 29;11(6). pii: E1221. doi: 10.3390/nu11061221. (Foscolou A et al.)

Poor Diet Linked with 1/3 of All New Colorectal Cancer Cases

Eating a healthy diet can help protect our health from a number of conditions and complications, so researchers wonder how diet might relate to cancer risk. In this study, researchers used models and dietary data to analyze the cancer cases from 2015. They found that 5.2% of all new cancer cases in 2015 could be attributed to poor diet, with 1.8% attributable to low whole grain consumption, 1.2% attributable to low dairy consumption, and 1% attributable to processed meats. The link with colorectal cancer shows the strongest relationship with diet, as poor diet is linked with 38.3% of all new colorectal cancer cases.
JNCI Cancer Spectrum. 2019 May 22;3(2):pkz034. doi: 10.1093/jncics/pkz034. (Zhang FF et al.)

Minimally Processed & Unprocessed Foods Linked with Weight Loss

Many ultra-processed convenience foods are designed to keep us coming back for more. In this study, researchers randomly assigned 20 adults to a diet of ultra-processed foods (packaged pastries, chicken nuggets, American cheese, deli meats, flavored fruit drinks, etc.) or unprocessed foods (spinach, nuts, fruit, chicken breast, plain Greek yogurt, avocado, sweet potato, bulgur, farro, etc.) for 2 weeks, immediately followed by the other diet for the next 2 weeks. The meals on both diets had the same number of calories, carbohydrates, fat, protein, sugar, sodium, and fiber, but participants could choose to eat as much or as little of the food that they wanted. People tended to eat 500 more calories on the ultra-processed diet, and gained about 2 pounds, while people tended to lose 2 pounds on the unprocessed diet. The categorization of ultra-processed vs unprocessed/minimally-processed is based on the NOVA system of food classification. While there are some concerns about the classifications used in the NOVA system (such as white rice and white flour being included in the “minimally processed” category alongside intact whole grains), helping direct consumers towards more wholesome, minimally-processed foods may be one strategy to address overeating and associated weight gain.
Cell Metabolism. 2019 May 16. pii: S1550-4131(19)30248-7. doi: 10.1016/j.cmet.2019.05.008. (Hall KD et al.)

Diets High in Red/Processed Meat and Low in Grain Fiber Linked with Colorectal Cancer

In a recent study, researchers enrolled over 400,000 participants and followed them for 5 years, analyzing their diet and health outcomes. The researchers found that the participants who ate the most red or processed meat had the highest risk of developing colorectal cancer. There was also an increased risk of colorectal cancer in participants who drank the most alcohol. Interestingly, the group that ate the most red and/or processed meat also tended to have a higher intake of alcohol, a lower intake of fruits and vegetables, and were more likely to smoke tobacco. The group with the highest intake of fiber from grains had the lowest risk of colorectal cancer. This study indicates that diets high in red or processed meats and lower in whole grains may be associated with an increased risk of colorectal cancer.
International Journal of Epidemiology. 2019 Apr 17. pii: dyz064. doi: 10.1093/ije/dyz064. (Bradbury KE, et al)

Switching to Whole Grains May Help Improve Insulin/Blood Sugar Management

Insulin is a hormone that helps your body manage your blood sugar, by keeping it from getting too high or too low. In this study, 13 adults with “pre-diabetes” were given a diet with either whole grains or refined grains for 8 weeks, then given a glucose test to assess how well their blood sugar was being managed. They then had a washout period of their normal diet for 8-10 weeks, before switching to the other diet for 8 weeks and taking the glucose test again, thus serving as their own controls. The whole grain diet improved the function of beta cells (the cells that secrete insulin) compared with the refined grain diet, and this effect was found to be independent of gut hormones (such as grehlin, the “hunger hormone”).
Molecular Nutrition and Food Research. 2019 Apr;63(7):e1800967. doi: 10.1002/mnfr.201800967. (Malin SK et al.)

Whole Grains Linked with 37% Lower Risk of Liver Cancer

Hepatocellular carcinoma, a common type of liver cancer, has been on the rise in the US, and researchers wonder if eating habits might play a role. In a study of 125,455 adults followed for 24 years, those eating the most whole grains (33g per day, or about 2 servings) were 37% less likely to develop hepatocellular carcinoma than those eating the least whole grains (7g per day, or less than half a serving). When looking at the isolated relationship of fiber, bran, and germ, the results were not statistically significant, indicating that whole grains are greater than the sum of their parts.
JAMA Oncology. 2019 Feb 21. doi: 10.1001/jamaoncol.2018.7159. [Epub ahead of print] (Yang W et al.)

Whole Grains and Fiber Linked with Lower Risk of Many Diseases

Whole grains are one of the most popular food sources of fiber, and both whole grains and fiber are important for overall health. In this study, researchers analyzed data from more than 200 studies encompassing 4,635 participants to better understand fiber and whole grains’ relationship with disease prevention. Fiber was linked with a 15-30% lower risk of heart disease, stroke, type 2 diabetes, colorectal cancer, and death, with similar findings for whole grains. The researchers noted a dose-response relationship for both whole grains and fiber, indicating that those who eat the most may confer an even greater benefit.
The Lancet. 2019 Feb 02;393(10170):434-445. doi: 10.1016/S0140-6736(18)31809-9 (Reynolds A et al.)

EAT-Lancet Commission Outlines a Healthy, Sustainable Diet

Diet is intimately linked both to human and environmental health. In this article, a commission of distinguished scientists from different fields set out to examine the components of a healthy diet and the link between diet and environmental health. Through an extensive review of literature, the researchers found that an ideal diet that meets basic nutritional needs and can be sustainably produced is mostly plant-based. Specifically, this diet is based around about 11 ounces vegetables, 9 ounces of dairy foods (a little over a cup of milk) 8 ounces of whole grains (about 8 servings, such as a slice of bread or a ½ cup cooked grains), 7 ounces of fruit, 3 ounces of legumes, 2 ounces of nuts, and an optional 2 ounces of other animal foods (like eggs, poultry, or meat) per day. The authors suggest that a global shift towards these dietary principles can prevent approximately 11 million deaths per year, and can sustainably produce enough food for the growing population without further damage to the environment.
Lancet.  2019 Feb 2;393(10170):447-492. doi: 10.1016/S0140-6736(18)31788-4. (Willett W et al)

Sprouted Triticale May Benefit Blood Sugar Management

Whole grains contain fiber, vitamins, minerals, and antioxidants, and sprouting grains may make these compounds more available. In this study, researchers fed volunteers a meal of sprouted whole wheat, sprouted whole grain triticale, or sugar and compared how these foods affected the volunteers blood sugar and insulin levels. People who ate the sprouted triticale had lower levels of blood sugar and insulin than those who ate sugar; the volunteers who ate sprouted wheat had lower blood sugar than those who had just sugar, but there was no difference in insulin response. Both grains were associated with improved blood sugar control, however this effect was strongest in the sprouted triticale group. This study indicates that whole grain triticale may be especially beneficial to blood sugar management.
Journal of Nutrition and Metabolism. 2019 Jan 10;2019:6594896. doi: 10.1155/2019/6594896. (Meija et al.)

Pages