Nutrition Guidelines: Why is There So Much Conflicting Information?

“Whole grains are good for you – whole grains are bad for your health.” “Eat meat – go vegetarian.” Who are you to believe – and why is there so much conflicting information about nutrition? The Paleos can’t see eye to eye with the vegetarians and the gluten-free crowd shuns the same whole grain foods many diet plans promote as healthy. Who’s right and how can there be so much contradictory information about nutrition?

Nutrition Studies Are Challenging to Carry Out

You might be tempted to jump on the latest studies and structure your diet around them, but such an approach could lead you astray. Nutritional research is fraught with issues, including the research itself. The only way to regulate a person’s intake of certain foods or food groups is to bring them into a controlled setting and monitor what they eat, hardly a situation that mimics real life. In addition, some studies rely on food recall and food questionnaires and look for correlations between intake of particular foods and markers of health. Unfortunately, most people aren’t very accurate at recalling what they ate yesterday, much less what they eat on a routine basis.

In nutritional studies, it’s also hard to control for factors, like physical activity, that can influence the study results. That’s why you can’t draw conclusions from a single study. It’s only after repeated studies reach similar conclusions that some credibility enters the picture.

It’s even more challenging when you study individual nutrients in isolation, for example, the effects of a particular vitamin taken in supplement form. Once you isolate a vitamin or mineral out of its natural context, it can have very different effects. An example is antioxidant vitamin supplements. Studies show foods that contain natural antioxidants – beta-carotene, vitamin A and vitamin E – seem to offer health benefits, but a study published in the Journal of American Medical Association showed supplementing with these nutrients in isolated form may actually increase mortality. That’s why it’s safest to get nutrients from food sources – not supplements.

 The Interaction Between Nutrients in Diet is Complex

Foods contain a complex mixture of vitamins, minerals, and phytochemicals that work in synergy with other dietary components like fiber to exert their effects. You eliminate these complex interactions when you study a nutrient in isolation. To complicate matters more, we’re all a little different from a genetic standpoint. Just because a study shows a link between eating whole grain foods and reduced mortality, as a recent Journal of the American Medical Association study did, doesn’t necessarily mean it’s the best option for you. A certain portion of the population is sensitive to gluten-containing grains, even if they don’t have documented celiac disease. If you fall into this category, a diet rich in whole grains isn’t a good choice, despite what the studies show.

Is Personalized Nutrition the Wave of the Future?

The fields of nutrigenetics and nutrigenomics focus on the interaction between food and genes. Nutrigenomics is a relatively new field that looks at how individual genetics impact how our bodies respond to particular foods, while nutrigenetics concentrates on how diet influences the expression of individual genes.

Also gaining ground is nutrigenetic testing, a type of testing that looks for variations in genes that control how an individual responds to diet. If a person has a variation in a single base pair in a sequence of DNA, it can affect how a particular nutrient is processed by the body, which in turn could have health implications. Most of us have some genetic variations that impact how we handle specific nutrients. The goal is to use nutrition, or in some case supplements, to compensate for these variations that could disrupt health.

 Nutrigenetic Testing Isn’t Ready for Prime Time

Although nutrigenetic testing is available through online sites, the tests aren’t closely regulated. Plus, once you get the results, you need someone to interpret the results and help you make the necessary changes to your diet and lifestyle. Plus, it’s not clear in every case what nutritional intervention is best. Gene-nutrient interactions are still far from being completely understood. Needless to say, there are lots of “kinks” to work out before nutrigenetic testing becomes mainstream. Once it does, you should be able to test your genes and have a personalized nutritional plan constructed based on your individual genetics. The goal, of course, would be to lower your risk for disease and optimize your health.

 There is No “Best” Diet

It would be simpler if there were a single eating plan that optimized the health of everyone who ate it, but we’re all a little different from a genetic standpoint. Until personalized nutrition becomes more mainstream, research supports eating a varied, nutrient-rich diet. Eating a variety of foods ensures you’re getting a diversity of nutrients and phytochemicals – but make sure you’re choosing nutrient-dense foods, not empty calories. Choose whole foods with an emphasis on fruits and vegetables in a variety of colors. Diversify the types of fruits and vegetables you eat on a daily basis rather than eating the same veggies every day.

Reduce processed carbs and eliminate added sugar from your diet. Sugar is completely devoid of nutritional value and only adds empty calories. The list of problems that sugar causes are long and sugar has no benefits other than serving as a source of energy.

Finally, don’t jump on every diet fad that comes along, whether it’s gluten-free, Atkins or Paleo. Although these diets may have health benefits for some people, they restrict large numbers of foods and reduce dietary diversity. A highly acclaimed eating plan that offers diversity and is supported by research is the Mediterranean diet, a diet rich in fruits, vegetables, whole grains, nuts and that emphasizes fish and lean poultry over red meat. The beauty of the Mediterranean diet is you have lots of foods to choose from and they’re not processed.

The Bottom Line

Keep it simple. It’s hard to go wrong eating a diverse diet that emphasizes whole foods. Nutrition may be confusing, but it doesn’t have to be complicated. Choose nutrient-dense whole foods and you’ll be doing good things for your health.

 

References:

JAMA. 2007;297(8):842-857. doi:10.1001/jama.297.8.842.

JAMA Intern Med. 2015;175(3):373-384.

J Nutrigenet Nutrigenomics. 2011 Jul; 4(2): 69-89.

Sofi F, Cesari F, Abbate R et al. Adherence to Mediterranean diet and health status: meta-analysis. BMJ 2008; 337: a1344. DOI: 10.1136/bmj.a1344.

 

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