2020 Dietary Guidelines Comments
Every 5 years, the United States Departments of Agriculture and Health and Human Services publish the Dietary Guidelines for Americans, a document that helps health professionals and policymakers guide Americans to make healthy food and beverage choices. The first print of the Scientific Report of the 2020 Dietary Guidelines Advisory Committee was recently released and is being provided to the public online for comments through August 13th. The Organic Center submitted comments that encourage the 2020 Dietary Guidelines Advisory Committee to revisit sustainability in the food system, because American diets must help sustain an ecosystem that can support crops over the long-term for a healthy population. Additionally, the Center's comments highlight the importance of incorporating impacts of agronomic production systems on nutrition and the potential impacts of exposure to chemicals from our food production system on children from pregnancy to age 24 months, because these aspects are critical for understanding the impacts our food system has on community health. Read the full comments below, and submit your own comments here.
Revisiting Sustainability in the Food System
The connection between the environment and our diets is especially important given data supporting the role of ecosystem services in food security. Food production takes a heavy toll on our natural resources. Without careful consideration of how to manage our land, water, and energy our agricultural production could decline significantly.
Additionally, recent research has increasingly shown a connection between human health and the health of the environment (1-3). This is especially true of soil health, which has several direct impacts on human health, such as (1) food availability and quality, (2) human contact with various chemicals in soil, (3) human contact with soil organisms, and (4) disposal of wastes (4, 5).
American consumers are also gaining interest in how their consumption habits affect the environment, and need guidance on complicated decisions regarding the confluence between diet, nutrition, and environmental awareness.
To meet future food needs and guide consumers in their food choices we will need to develop Guidelines that incorporate sustainability. This will enable the Guidelines to serve not only as a tool to direct consumer eating habits toward healthier alternatives, but also to shift eating habits toward less resource-intensive diets. In this regard, sustainability in the Dietary Guidelines for Americans would serve to improve individual and population dietary choices and patterns, and act as an incentive for improvement of environmental conservation in agricultural and production practices that meet food and nutrition needs.
The connection between food production and nutrition also highlights the importance of considering food systems in the Dietary Guidelines. For example, many antioxidant compounds that are nutritionally beneficial for humans are created in response to oxidative stress the plant experiences (6). This stress can be caused by many environmental factors, such as herbivory by insects, low nutrient levels, etc. Because crops that are grown without pesticides experience more stress than conventional crops they may produce higher levels of antioxidants in response to that stress. Additionally, the growth-differentiation balance hypothesis states that in high nutrient environments, plants will spend their resources creating new plant tissue rather than secondary metabolites (7). In less rich conditions, however, growth is limited by lack of nutrients, so more resources will be available to be spent on secondary metabolites. Thus, as nutrient levels decrease from high to intermediate, antioxidant levels increase.
Because organic crops are grown in conditions that have both increased oxidative stress from herbivory and other environmental conditions, and are grown in soil with intermediate nutrient levels, several studies have shown that organic crops tend to have higher levels of antioxidants (8).
Another example of food production impacting nutrition can be found in dairy and meat raised under conventional conditions versus in conditions that require pasture access, such as under organic management. One meta-analysis found that organic milk had 56% higher omega-3 fatty acid levels, higher levels of conjugated linoleic acid (CLA), iron, vitamin E, and carotenoids than conventional milk (9). Another study found that organic meat contains nearly 50% higher levels of beneficial omega-3 fatty acids than non-organic meat due to required grazing and feeding practices (10).
Childhood Exposure to Agronomic Chemicals
The impacts of agronomic production on children from pregnancy to age 24 months are important to incorporate into Dietary Guidelines for Americans, because their food choices directly impact the health of children. This is especially true when it comes to pesticide exposure, because over the last decade dozens of studies have shown associations between exposures to agricultural pesticides and many serious health concerns. For example, recent research has shown that pesticide exposure can harm reproductive health, is linked with respiratory illness, rheumatoid arthritis, coronary heart disease, renal disease, and Parkinson’s disease, and can contribute to cancers such as thyroid cancer, prostate cancer, colorectal cancer, lung cancer, and breast cancer (11-17).
Children in agricultural communities are at particular risk for pesticide exposure at a time in their lives when they are most vulnerable to harmful chemicals. On average, children have higher exposures to environmental chemicals than adults because they eat, drink, and breath more than adults on a per-bodyweight basis. They also spend time near the floor where house dust may be contaminated with pesticides. Children explore their environments with their hands and mouths, increasing exposures even more. They also have undeveloped metabolic pathways and thus often have a reduced ability to metabolize toxins such as pesticides into non-toxic water soluble forms that can be excreted as urine.
Even before birth exposure to pesticides can have long-term or permanent impacts on children’s lives. Prenatal exposure to chemicals can alter the development of networks that build our individual neural architecture. Being exposed to a neurotoxic chemical during this process can permanently alter the structure of that architecture, causing long-term impacts.
Results from studies examining prenatal exposure to pesticides are concerning, with studies showing that exposure before birth may be linked to several conditions, including the development of obesity and metabolic disorders, developmental problems, poorer neurodevelopment, and decreased IQ among other health challenges (18-21). Additionally, maternal exposure to organophosphate pesticides during pregnancy is associated with earlier labor, poorer neonatal reflexes, and developmental disorders and increased risk of attention problems in children (22-24).
We believe that incorporating sustainability in the food system, the impacts of agronomic production systems on nutrition, and the potential impacts of exposure to chemicals from our food production system on children from pregnancy to age 24 months is critical for a holistic Dietary Guidelines for Americans.
1. Cole DC, Eyles J, Gibson BL, Ross N. Links between humans and ecosystems: the implications of framing for health promotion strategies. Health Promotion International. 1999;14(1):65-72.
2. Pongsiri MJ, Roman J. Examining the Links between Biodiversity and Human Health: An Interdisciplinary Research Initiative at the U.S. Environmental Protection Agency. EcoHealth. 2007;4(1):82-5.
3. Rabinowitz P, Conti L. Links Among Human Health, Animal Health, and Ecosystem Health. Annual Review of Public Health. 2013;34(1):189-204.
4. Brevik EC, Steffan JJ, Burgess LC, Cerdà A. Links Between Soil Security and the Influence of Soil on Human Health. In: Field DJ, Morgan CLS, McBratney AB, editors. Global Soil Security: Progress in Soil Science: Springer; 2017.
5. Brevik EC, Pereg L, Pereira P, Steffan JJ, Burgess LC, Gedeon CI. Shelter, clothing, and fuel: Often overlooked links between soils, ecosystem services, and human health. Science of The Total Environment. 2019;651:134-42.
6. Fürstenberg-Hägg J, Zagrobelny M, Bak S. Plant defense against insect herbivores. Int J Mol Sci. 2013;14(5):10242-97.
7. Herms DA, Mattson WJ. The Dilemma of Plants: To Grow or Defend. The Quarterly Review of Biology. 1992;67(3):283-335.
8. Barański M, Średnicka-Tober D, Volakakis N, Seal C, Sanderson R, Stewart GB, et al. Higher antioxidant and lower cadmium concentrations and lower incidence of pesticide residues in organically grown crops: a systematic literature review and meta-analyses. British Journal of Nutrition. 2014;112(5):794-811.
9. Średnicka-Tober D, Barański M, Seal CJ, Sanderson R, Benbrook C, Steinshamn H, et al. Higher PUFA and n-3 PUFA, conjugated linoleic acid, α-tocopherol and iron, but lower iodine and selenium concentrations in organic milk: a systematic literature review and meta- and redundancy analyses. British Journal of Nutrition. 2016;115(6):1043-60.
10. Średnicka-Tober D, Barański M, Seal C, Sanderson R, Benbrook C, Steinshamn H, et al. Composition differences between organic and conventional meat: a systematic literature review and meta-analysis. The British journal of nutrition. 2016;115(6):994-1011.
11. Jones RR, Barone-Adesi F, Koutros S, Lerro CC, Blair A, Lubin J, et al. Incidence of solid tumours among pesticide applicators exposed to the organophosphate insecticide diazinon in the Agricultural Health Study: an updated analysis. Occupational and Environmental Medicine. 2015;72(7):496.
12. Lerro CC, Koutros S, Andreotti G, Hines CJ, Blair A, Lubin J, et al. Use of acetochlor and cancer incidence in the Agricultural Health Study. International journal of cancer. 2015;137(5):1167-75.
13. Lewis-Mikhael A-M, Bueno-Cavanillas A, Ofir Guiron T, Olmedo-Requena R, Delgado-Rodríguez M, Jiménez-Moleón JJ. Occupational exposure to pesticides and prostate cancer: a systematic review and meta-analysis. Occupational and Environmental Medicine. 2016;73(2):134.
14. Kannarkat GT, Cook DA, Lee JK, Chang J, Chung J, Sandy E, et al. Common genetic variant association with altered HLA expression, synergy with pyrethroid exposure, and risk for Parkinson’s disease: an observational and case–control study. npj Parkinson's Disease. 2015;1(1):15002.
15. Lebov JF, Engel LS, Richardson D, Hogan SL, Hoppin JA, Sandler DP. Pesticide use and risk of end-stage renal disease among licensed pesticide applicators in the Agricultural Health Study. Occupational and Environmental Medicine. 2016;73(1):3.
16. Han J, Zhou L, Luo M, Liang Y, Zhao W, Wang P, et al. Nonoccupational Exposure to Pyrethroids and Risk of Coronary Heart Disease in the Chinese Population. Environmental Science & Technology. 2017;51(1):664-70.
17. Parks CG, Hoppin JA, De Roos AJ, Costenbader KH, Alavanja MC, Sandler DP. Rheumatoid Arthritis in Agricultural Health Study Spouses: Associations with Pesticides and Other Farm Exposures. Environ Health Perspect. 2016;124(11):1728-34.
18. Eskenazi B, Harley K, Bradman A, Weltzien E, Jewell NP, Barr DB, et al. Association of in Utero Organophosphate Pesticide Exposure and Fetal Growth and Length of Gestation in an Agricultural Population. Environ Health Perspect. 2004;112(10):1116-24.
19. Young JG, Eskenazi B, Gladstone EA, Bradman A, Pedersen L, Johnson C, et al. Association Between In Utero Organophosphate Pesticide Exposure and Abnormal Reflexes in Neonates. NeuroToxicology. 2005;26(2):199-209.
20. Eskenazi B, Marks AR, Bradman A, Harley K, Dana BB, Caroline J, et al. Organophosphate Pesticide Exposure and Neurodevelopment in Young Mexican-American Children. Environ Health Perspect. 2007;115(5):792-8.
21. Marks AR, Harley K, Bradman A, Kogut K, Barr DB, Johnson C, et al. Organophosphate pesticide exposure and attention in young Mexican-American children: the CHAMACOS study. Environ Health Perspect. 2010;118(12):1768-74.
22. Debost-Legrand A, Warembourg C, Massart C, Chevrier C, Bonvallot N, Monfort C, et al. Prenatal exposure to persistent organic pollutants and organophosphate pesticides, and markers of glucose metabolism at birth. Environmental Research. 2016;146:207-17.
23. Rauh VA, Garcia WE, Whyatt RM, Horton MK, Barr DB, Louis ED. Prenatal exposure to the organophosphate pesticide chlorpyrifos and childhood tremor. NeuroToxicology. 2015;51:80-6.
24. Gunier Robert B, Bradman A, Harley Kim G, Kogut K, Eskenazi B. Prenatal Residential Proximity to Agricultural Pesticide Use and IQ in 7-Year-Old Children. Environ Health Perspect.125(5):057002.