By U.S. Government Web Portal
August 12, 2020
Mr. Brandon Lipps
Deputy Under Secretary for Food, Nutrition & Consumer Services
U.S. Department of Agriculture

Capt. Paul Reed
Deputy Assistant Secretary for Health
Acting Director, Office of Disease Prevention and Health Promotion
Office of the Assistant Secretary for Health
U.S. Department of Health and Human Services

Re: 2020 U.S. Dietary Guidelines Advisory Committee Scientific Report (Chapter 11)

Dear Mr. Lipps and Capt. Reed:

We are providing our comments regarding Alcoholic Beverages Chapter 11 of the Scientific Report of the
2020 Dietary Guidelines Advisory Committee (DGAC). The perspective and experience associated with the development of Canada’s own Low Risk Alcohol Drinking Guidelines (LRDG) may help inform current discussions.

Based on consideration of that LRDG work and of the scientific evidence, we contend that the tightening of U.S. drinking guidelines is not warranted, and that the process followed should be reconsidered.

Throughout our respective histories, Canada and the United States have had strong cultural, economic and trade ties. Collectively, the beverage alcohol sector on both sides of the border supports millions of jobs including those in industry as well as in the foodservice, hospitality and tourism sectors, all of which are struggling as a result of the COVID-19 pandemic. Beverage alcohol supply chains are also interconnected, extending out to cross-border movement of agricultural products, and other raw and finished materials.

Given these linkages our interest in the current U.S. discussions is understandable. Our familiarity with the process undertaken to develop Canadas drinking guidelines may also provide helpful insights.

Canada’s LRDG

Canada’s LRDG offer constructive and useful advice on healthy and safer drinking, while warning about the risks of exceeding safe drinking recommendations of 15 drinks weekly for men and 10 drinks for women, as well as setting daily drinking limits. A drink in Canada is regarded as 13.6 grams of alcohol versus 14 grams in the United States.

The LRDG recognize that there is a place for moderate alcohol consumption within society, and efforts should be directed toward informing those who choose to drink about sensible levels of consumption, balancing both risks and benefits to ensure the relevance of the LRDG to the Canadian public.

The LRDG support what Canada’s National Alcohol Strategy refers to as a culture of moderation “a new way of thinking about alcohol use that includes an understanding of when, when not, and how much to drink appropriate motivations for drinking and settings in which responsible drinking should take place”.

LRDG advice was developed through a stringent review process involving an independent expert advisory panel of alcohol researchers “which made extensive use of the results of numerous systematic reviews and meta-analyses including some critically appraised Canadian studies…” CCSA, Background on LRDG Development and Methodology).

Further, the report released by the LRDG expert advisory panel was also subject to a rigorous peer review by three international researchers with specific expertise in alcohol epidemiology and alcohol policy.

Concerns about the U.S. DGAC Process & Recommendations

Review of Evidence Base

In contrast to the process followed in developing Canadas LRDG US beverage alcohol guideline development involved only one member of the Beverages Subcommittee of the DGAC who had an academic interest in alcohol. As a result, no allowance was made for competing professional points of view or a diversity of views based on expertise in alcohol-related issues. The process also enabled confirmation bias, including recommending conclusions from self-produced alcohol research work.

It is not surprising then under these circumstances that recommendations were made to tighten or revise the guidelines downwards for men in particular, even though no new evidence was presented in the systematic review process of 60 alcohol studies supporting such a change. Most of the 60 studies also controlled for a large number of factors, addressing any concerns about confounding bias.

In effect, the studies reviewed in Chapter 11 of the Scientific Report continue to support the well established lower risk for light-moderate drinkers, compared to abstainers despite the conclusions drawn. While the authors focus on lowest risk estimates (a departure from previous U.S. guideline reviews), risk for men did not appear to increase until beyond two drinks or 28g/day. In many studies, the heaviest drinking group was defined as 20+, 28+, or 30+ g/day. Nearly a dozen other meta-analyses supportive of the J-curve were not included in the Scientific Report.

Further, the authors also disregarded the systematic review protocol, instead placing substantial emphasis on ungraded out-of-scope references (mainly Mendelian Randomization (MR) studies). Of the 15 MR studies cited, only one met the stated criteria for the systematic review. The MR studies are used to discount the majority of the research reporting a protective effect for moderate alcohol consumption.

But MR methodology applied to alcohol and health research has been questioned in the scientific community. As an example, in a critical analysis of the methodology, Mukamal, K.J et. al. (European Journal of Epidemiology 2019) note that because of limitations MR should be viewed as another type of observational study and therefore not seen to negate the existing body of evidence supporting the J-curve relationship between drinking and cardiovascular disease.

Guideline Advice

Chapter 11 of the DGAC Scientific Report recommends limits for both men and women be set at 1 drink per day on days when alcohol is consumed, reducing by 50 percent the current levels for men, and discarding several decades of research on gender differences around drinking effects. The Report in part concludes that “Overall alcohol is an unhealthy substance and the United States population is far from achieving alcohol consumption levels that would meaningfully reduce alcohol-related harms”.

In effect, where any alcohol is deemed as unhealthy, the guideline recommendations being brought forward are not about encouraging sensible drinking. Unrealistically low and impractical they run counter to the goal of developing and supporting a culture of moderation.

The public will follow guideline advice only if they believe it is useful to helping them stay within the boundaries of what most already believe to be reasonable and non-harmful behaviour. The current recommendations fail in this respect, and given the weakness and distortion of evidence, they cannot be considered as legitimate or credible.

Conclusion

Consideration of the approach in developing Canada’s LRDG raises concerns about the proposed United States alcohol consumption guidelines, and their credibility and public acceptance. The proposed guideline advice is not supported by the scientific evidence, and the process followed to arrive at the recommendations is flawed, lacking allowance for competing alcohol expert insights and opinions. The revision of drinking guideline levels is not warranted

We encourage the United States to reconsider the process followed and to let the evidence determine the direction for the development of these guidelines.

Sincerely,