The alcohol section of the new Dietary Guidelines Advisory Committee report (PDF) could represent a radical departure from the 2005 Dietary Guidelines1 if its conclusions are reflected in the final Dietary Guideline for alcohol scheduled to come out later this year. The proposed increase in daily drinking guidelines that would be defined as “moderate” drinking, the lack of randomized studies on the health effects of alcohol consumption, and potentially dangerous public health messages are some of the reasons these proposed changes are concerning – and worth your time to submit comments by July 15.
The current Dietary Guidelines for alcohol provides drinking guidelines outlining the safest way to consume alcohol for the full range of the U.S. population that already drinks alcohol: up to 2 drinks per day for men and up to 1 drink per day for women (2/1 daily consumption guidelines). However, the new Advisory Committee report proposes that 2/1 consumption guidelines be based on average, rather than daily, consumption. Furthermore, the report would explicitly define “moderate” drinking as drinking up to 4 drinks per day for men and 3 drinks for women (4/3 daily consumption guidelines), so long as the average limits are not exceeded.
If most drinkers drank on a daily basis, then 2/1 daily guidelines would be identical to the proposed 2/1 average guidelines. But this is not how most people drink in the U.S. For example, among men and women who drink an average of <2/1 drinks, respectively, more than three-quarters consume alcohol only 2-3 days per week or less.2 Therefore, with respect to the proposed guidelines, most persons' consumption on any given day would not be constrained by the proposed new weekly (i.e. “average”) guideline, but would only be affected by the new daily guideline. So in fact the net effect of the proposed change amounts to an endorsement for most men to consume up to 4 drinks and for most women to consume up to 3 drinks on days they actually consume alcohol.
In any event, the proposed change represents a doubling of the daily guideline for men, and a tripling of the daily guideline for women. Although drinking 4 drinks for men and 3 drinks for women falls just short of thresholds that define 'binge' drinking and is not generally pathologic, relaxing guidelines that might cause some to increase their drinking to these levels is neither safe nor desirable from a public health perspective. Specifically, drinking at these levels results in impairment-level blood alcohol concentrations (BACs) for most drinkers, including legal intoxication-level BACs (0.08% or greater) for some, particularly women.3 Furthermore, epidemiologic studies confirm that drinking 4/3 drinks (or to BACs typically associated with 4/3 consumption) is associated with increased risk for unintentional injuries, including motor vehicle crashes.4-6 And daily consumption exceeding the current Dietary Guidelines is also associated with chronic disease outcomes such as hypertension and overweight.7 Even among those who consume an average of <2/1 drinks, the report offers no evidence (nor are we aware of any) that drinking 4 or 3 drinks during drinking days is safer for any health outcome compared with consuming fewer drinks.
The current (2005) Dietary Guidelines explicitly discourage anyone from beginning to drink or drinking more frequently on the basis of health considerations.1 But the tone of this new report creates an impression that alcohol consumption is a viable therapeutic option to be considered and/or discussed with one's physician. To date, however, there have been no (zero) randomized controlled trials (RCTs) of low-dose alcohol and any mortality or morbidity outcome. RCTs are the level of evidence required to approve a new pharmaceutical agent, and should be for an agent that is also a leading health hazard and recognized human carcinogen.8, 9 Furthermore, there is good evidence that existing observational studies of “moderate” drinking are likely confounded in ways that bias results in favor of moderate drinkers.10-12 The bottom line is that reams of consistent observational studies can be consistently wrong and lead to erroneous conclusions with mortal consequences, as in the case of hormone replacement therapy.13, 14
Relaxing guidelines delineating “moderate” drinking is not like recommending someone take more vitamins. Alcohol is the third leading preventable cause of death in the U.S.,15 and causes many net excess deaths even assuming a cardio-protective effect among those with low average consumption.16 In addition, there are risks associated with even low levels of consumption (e.g., breast cancer),17 and others who begin to drink or who increase their consumption may encounter alcohol-related problems or end up drinking excessively. Therefore, in the absence of data from randomized trials and on the basis of practical public health considerations, the proposed change to the Dietary Guidelines is a prescription for ill health and adverse social consequences.
You can submit comments about the report until July 15. Even if you don't have much time, please consider writing something — don't let the perfect be the enemy of the good. Click here then click on the “SUBMIT written comments” button.
Timothy S. Naimi, M.D., M.P.H.
Boston Medical Center
1. US Department of Agriculture and US Department of Health and Human Services. Dietary Guidelines for Americans, 2005 (chapter 9, alcoholic beverages). Accessed May 21, 2010.
2. Naimi TS, Brown DW, Brewer RD. Binge alcohol consumption and cardiovascular risk factors among “moderate” drinkers in the U.S. Paper presented at: 33rd Annual Scientific Meeting of the Research Society on Alcoholism; June 26-30 2010; San Antonio, Texas.
3. The Century Council. B4 U Drink Educator. http://b4udrink.org/bae. Accessed July 8, 2010.
4. Vinson DC, MacLure M, Reidinger C, Smith GS. A population-based case-crossover and case-control study of alcohol and the risk of injury. J Stud Alcohol. 2003;64:358-366.
5. Zador PL, Krawchuk SA, Voas RB. Alcohol-related relative risk of driver fatalities and driver involvement in fatal crashes in relation to driver age and gender: an update using 1996 data. J Stud Alcohol. 2000;61:387-395.
6. Transportation Research Board. Low Blood Alcohol Concentrations: Scientific and Policy Issues. National Research Council; 2001. www.icadts.org/coreports/TRBLowBACWorkshop.pdf#page=12 . Accessed July 7, 2010.
7. Fan AZ, Russell M, Naimi TS, et al. Patterns of alcohol consumption and the metabolic syndrome. J Clin Endocrinol Metab. 2008;93:3833-3838.
8. Bagnardi V, Blangiardo M, La Vecchia C, Corrao G. A meta-analysis of alcohol drinking and cancer risk. Br J Cancer. 2001;85:1700-1705.
9. National Toxicology Program. Alcoholic Beverage Consumption. http://ntp.niehs.nih.gov/ntp/roc/eleventh/profiles/s007alco.pdf. Accessed July 2, 2010.
10. Naimi TS, Brown DW. Cardiovascular risk factors and confounders among nondrinking and moderate-drinking U.S. adults. Am J Prev Med. 2005;28:369-373.
11. Fillmore KM, Kerr WC, Stockwell T, et al. Moderate alcohol use and reduced mortality risk: systematic error in prospective studies. Addiction Research and Theory. 2006;14:101-132.
12. Jackson R, Broad J, Connor J, Wells S. Alcohol and ischemic heart disease: probably no free lunch. Lancet. 2005;366:1911-1912.
13. Grady D, Herrington D, Bittner V, et al. Cardiovascular disease outcomes during 6.8 years of hormone therapy – heart and estrogen/progestin replacement study follow-up (HERS II). JAMA. 2002;288:49-57.
14. Women's Health Initiative Investigators. Risks and benefits of estrogen plus progestin in healthy postmenopausal women – principal results from the Women's Health Initiative randomized controlled trial. JAMA. 2002;288:321-333.
15. Mokdad AH, Stroup D, Marks JS, Gerberding J. Actual Causes of Death in the United States, 2000. JAMA. 2004;291:1238-1245.
16. Centers for Disease Control and Prevention. Alcohol-Related Disease Impact (ARDI). www.cdc.gov/alcohol/ardi.htm. Accessed March 28, 2008.
17. Lauer M, Sorlie P. Alcohol, cardiovascular disease, and cancer: treat with caution. J Nat Cancer Inst. 2009;101:282-283.