National Nutrition Month: Evidence Based Nutrition

March is National Nutrition Month

Just in time, the United States Department of Agriculture and Department of Health and Human Services released their Scientific Report of the 2015 Dietary Guidelines Advisory Committee. They are accepting public comments through April 8, 2015. The report provides conclusions to several questions regarding the impact of nutrition on health to inform the official Dietary Guidelines for Americans, 2015 expected to be released this fall.

Evidence Based

All conclusions in the report are based on systematic reviews of the most current scientific evidence either assisted by the USDA's Nutrition Evidence Library (NEL) or from already published systematic reviews, "Each step of the process was documented to ensure transparency and reproducibility. Specific information about each review is available at www.NEL.gov..." The strength of evidence on which each recommendation is made was graded using the following parameters... 

Dietary Cholesterol is No Longer a Concern

This report has been making headlines for recommending that cholesterol in food is no longer a concern. The report itself states,

Previously, the Dietary Guidelines for Americans recommended that cholesterol intake 643 be limited to no more than 300 mg/day. The 2015 DGAC will not bring forward this recommendation 644 because available evidence shows no appreciable relationship between consumption of dietary cholesterol and serum cholesterol, consistent with the conclusions of the AHA/ACC report. 2, 35 Cholesterol is not a nutrient of concern for overconsumption. 

The studies they cite to support this include... 

Eckel RH, Jakicic JM, Ard JD, de Jesus JM, Houston Miller N, Hubbard VS, et al. 2013 AHA/ACC 2950 guideline on lifestyle management to reduce cardiovascular risk: a report of the American College of 2951 Cardiology/American Heart Association Task Force on Practice Guidelines. Circulation. 2014;129(25 2952 Suppl 2):S76-99. PMID: 24222015. 

Shin JY, Xun P, Nakamura Y, He K. Egg consumption in relation to risk of cardiovascular disease and 3054 diabetes: a systematic review and meta-analysis. Am J Clin Nutr. 2013;98(1):146-59. PMID: 23676423.

A grade of evidence regarding dietary cholesterol is not provided directly. Rather, the evidence is "strong" that patterns of eating that reduces risk of cardiovascular disease are... 

...patterns characterized by higher consumption of vegetables, fruits, whole grains, low-fat dairy, and seafood, and lower consumption of red and processed meat, and lower intakes of refined grains, and sugar-sweetened foods and beverages relative to less healthy patterns; regular consumption of nuts and legumes; moderate consumption of alcohol; lower in saturated fat, cholesterol, and sodium and richer in fiber, potassium, and unsaturated fats. 

Deciphering Headlines

Some headlines referring to the report may be misleading. For example, some stories are highlighting that the report concludes coffee consumption can prevent type 2 diabetes, Parkinson's disease, Alzheimer's disease, and is not associated with negative pregnancy outcomes. However, none of the evidence for these conclusions is strong and range from limited to moderate. As you are reading headlines, be sure to check the strength of evidence. While the report is over 500 pages long, you can hold down your CTRL and F key at the same time to bring up a search box and in that box type the phrase "DGAC Grade." This will allow you to navigate directly to the strength of evidence for each conclusion in the report.