Using nutrition to modulate health effects of environmental pollutants

Michelle A. MendezDept of NutritionUNC-Chapel Hill

NUTRITION MATTERS: Deaths attributed to 19 leading factors

9 of top 19 global causes of death are nutritional--------------------------------------Source: WHO Global Burden of Diseasehttp://www.who.int/healthinfo/global_burden_disease/global_health_risks/en/index.html

Top 10 causes of disability-adjusted life year’s lost in high-income countries

Recent evidence: Diet may also interact with contaminants to affect health Benefits:

Diet may help to reduce negative health effects of certain contaminants

Risks: Diet can also be a source of contaminants, or may

strengthen risk of contaminant exposure

Minimizing risks and maximizing benefits is essential

Fruits, vegetables and related nutrients may reduce contaminant risks

Mechanisms may involve antioxidant vitamins (e.g. vitamins C & E) as well as other components of fruits and vegetables

A few examples - air pollution Guxens et al 2012 in Spain - higher exposure to air pollution

in pregnancy associated with lower infant mental development scores only if mothers had low F&V intakes

Raaschou-Nielsen et al 2012 in Denmark - residential air pollution associated with a 25% increase in cardiovascular mortality overall, 45% if consumed <200grams/day of F&V

Fruits, vegetables and related nutrients may reduce contaminant risks (cont)

Folate Gamble et al 2006 found folate supplements to increase

metabolism/excretion of arsenic in a population with contaminated water in Bangladesh

Arsenic is a carcinogen recently found to increase risk of diabetes and perhaps hypertension, as well as impaired child neurodevelopment

Also influences epigenetics (DNA methylation)

Vitamin C Duarte-Salles et al found higher intakes of vitamin C during

pregnancy to eliminate a 100g reduction in birth weight associated with exposure to dietary PAHs in a Spanish population

Other potentially beneficial dietary factors

Omega-3 fatty acids e.g. in fatty fish May help to reduce risk of atherosclerosis associated

with contaminants found in the environment such as PCBs (polychlorinated biphenyls)

Other potentially beneficial dietary factors

Breastfeeding May reduce effects of prenatal exposure to

chemicals such as tobacco Mendez et al 2008 found a 4-fold increase in overweight

among children whose mothers smoked in early pregnancy, but no increase among those breastfed for 6mo or more

Potentially harmful dietary factorsExcessive dietary fat, energy density

May increase impact of “obesogenic” chemicals May cause cardiovascular disease, cancers

Contaminants in the food chain Packaging products, additives

e.g. bisphenol A, phthalates: may be obesogens, carcinogens, or affect neurodevelopment

Water pollutants, widely used chemicals e.g. arsenic, mercury, pesticides, flame retardants: may be carcinogens,

neurotoxins, diabetogens or obesogens

Air pollutants, cooking/combustion products e.g. acrylamide, PAHs from high temp cooking, smoking, traffic: may be

carcinogens, neurotoxic or affect growth

High-fat diet may strengthen effects of and obesogenic chemicals

Wei et al 2012 found Typical weight gain in

mice fed a normal diet, slight increase if fed BPA

Excess weight gain with a high fat diet, significantly increased if also fed BPA

Similar dependence on a high-fat diet has been suggested for other chemical “obesogens” (e.g. discussed in Hennig article)

High-fat diet may strengthen effects of and obesogenic chemicals

We found in a study from Spain that prenatal exposure to the pesticide DDT (which persists in the environment) was Associated with a 2-fold increase in overweight at age

6y among children consuming a higher-fat diet

Not associated with overweight at age 6y among children who were consuming a lower-fat diet

Source: Valvi, Mendez et al, Environmental Health Perspectives 2012

Balancing the risks and benefits Potentially reducing health effects of contaminants

provides one more reason for a healthy diet Rich in fruits, vegetables, whole grains, and omega-3

fatty acids Lower in saturated, trans and omega-6 fatty acids AND

low dietary contaminants! Important to start this diet as early as possible to maximize long-

term health and development Diet during pregnancy, sustained breastfeeding, and beyond