Michelle Mendez` presentation

Using nutrition to modulate health
effects of environmental pollutants
Michelle A. Mendez
Dept of Nutrition
UNC-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 Disease
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
 Diet
may help to reduce negative health effects of
certain contaminants
 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)
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 factors
 Excessive
dietary fat, energy density
May increase impact of “obesogenic” chemicals
 May cause cardiovascular disease, cancers
 Contaminants
Packaging products, additives
e.g. bisphenol A, phthalates: may be obesogens,
carcinogens, or affect neurodevelopment
Water pollutants, widely used chemicals
in the food chain
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 longterm health and development
Diet during pregnancy, sustained breastfeeding, and beyond