WASHINGTON, March 18, 2015 – Dietary science has always been shifting and incomplete. That’s the reason the federal dietary guidelines are required by law to be revised every five years. But recent shifts in scientific thinking – most notably about dietary cholesterol – and increasingly public debates among scientists about sodium, saturated fat and other issues have emboldened critics inside and outside Congress to raise questions about a range of policy matters.

That uncertain nature of dietary science could be used in coming months to buttress Republican attacks on the Obama administration’s ongoing campaign to fight childhood obesity and other health issues. The upcoming dietary guidelines, school nutrition standards, nutrition labeling and the Food and Drug Administration’s effort to eliminate trans fats from the food supply all could be affected.

The reversal in scientific thinking on dietary cholesterol was reflected in the recent recommendations by the Dietary Guidelines Advisory Council. Concerns about cholesterol had long been a problem for the egg industry. Nullifying years of advice to consumers, the committee said “cholesterol is not considered a nutrient of concern for overconsumption. “The current guidelines recommend consuming no more than 300 milligrams of cholesterol a day; a single egg contains about 200.

Patrick Skerrett, executive editor of Harvard Health, a publication of Harvard Medical School, is warning that the change on cholesterol could be seen as weakening the case for dietary advice on other issues.

“Science, including nutrition science, is a process of change,” he wrote. “New findings emerge that nudge aside old thinking and prompt new recommendations. That’s easy for someone like me to say, since I closely follow nutrition science and research and understand how they work. But for folks who don’t, a change in the recommendations about cholesterol in food is likely to be seen as another dietary flip-flop and undermine confidence in what’s known about healthy eating.”

The chairman of the House Ag Appropriations Subcommittee, Robert Aderholt, wasted no time bringing up the cholesterol issue last month when he opened his hearings on the fiscal 2016 budget for the Agriculture Department and FDA. Agriculture Secretary Tom Vilsack was the main witness, and Aderholt wanted to get him on the record disowning a separate, far controversial, recommendation by the advisory council – its suggestion that the 2015 Dietary Guidelines for Americans take into account the environmental impact of producing meat and promote a “plant-based diet.”

Aderholt suggested that the science is too shaky on that and other issues to take such stands on meat.

Vilsack acknowledged that “in many areas science is evolving and science changes” and promised to “color within the lines” on the final dietary guidelines, a clear indication that the environmental advice will be discarded.

FDA’s labeling requirement for trans fats already has led the food industry to drastically reduce their use of partially hydrogenated oils. Subcommittee member Andy Harris, a Maryland Republican and physician who joined the panel this year, told FDA Commissioner Margaret Hamburg that she can’t scientifically justify the health benefits of eliminating trans fats. “The evidence is not good that you’re achieving anything,” Harris told Hamburg.

Trans fat intake among American consumers dropped from 4.6 grams per day before the labeling requirement to about a gram per day in 2012.

Harris also suggested the 2015 dietary guidelines should recognize that there is “real uncertainty” about what the sodium limits should be for different groups of people. Hamburg assured him that “we are deeply involved in examining the science” but that there is a “very large body of literature that shows that reducing sodium does have significant, meaningful impacts.”

In fact, there is relatively little disagreement that Americans consume more sodium than they should, and that sodium plays a role in high blood pressure and cardiovascular disease, but there is a bigger debate about what are the safe limits for specific age groups.

School food-service directors are raising scientific questions about the sodium limits in USDA’s school lunch standards. At the School Nutrition Association’s legislative policy meeting earlier this month, attendees repeatedly challenged USDA officials on the lack of scientific evidence about appropriate levels of sodium consumption in children. 

The scientific debate is reflected in a six-page letter that USDA sent to Aderholt in January outlining the findings of the Dietary Guidelines Advisory Committee.

The committee found that there was “strong evidence” that people who need to lower their blood pressure would benefit from reducing their sodium intake and “moderate evidence” that blood pressure in children increases as sodium intake rises. The committee said that there was “inconsistent and insufficient” evidence as to whether lowering sodium intake below 2,300 milligrams a day would raise or lower the risk of cardiovascular disease in the general population.

The letter points out that the average school child consumes 3,279 milligrams a day, well above the 1,900 to 2,300 limit for children recommended by the Institute of Medicine and used by USDA in developing its school standards.

The fiscal 2016 omnibus spending bill includes a provision blocking a further reduction in sodium restrictions for school meals until “scientific research establishes the reduction is beneficial for children.” The provision would expire with the end of the fiscal year, and SNA is backing legislation proposed by Sen. John Hoeven, R-N.D., that would go a step further and permanently freeze existing limits.

Under the current standard, which took effect with the current school year, school lunches are limited to 1,230 milligrams for elementary kids, 1,360 for middle schoolers and 1,420 milligrams for high school students. Those limits are set to drop to 935 milligrams, 1,035 milligrams and 1,080 milligrams respectively in 2017 and then drop again in 2022.

Hoeven hopes to get his provisions included in a rewrite of the Healthy, Hunger-Free Kids Act, which expires Sept. 30. Another option is to try to write some version of the legislation into USDA’s fiscal 2016 spending bill as a short-term fix.


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