Alzheimer’s disease may not simply be a disease of old age. Cases of Alzheimer’s have been increasing steadily over the past few decades and it has been assumed that this is because the population is growing older due to healthier lifestyles and improved medical care.
However, new research has found a link between the use of the agricultural pesticide DDT and Alzheimer’s – maybe we really are poisoning ourselves?
American health scientists observed a link between DDT and Alzeimer’s. People with Alzeimer’s tend to have around four times more DDT in their body than a healthy person.
DDT was used extensively after World Ward II. It was eventually banned in the USA in 1972 and later in other countries. However, it is still used in many parts of the world today because it is so effective at reducing malaria – a disease which kills many more people than Alzheimer’s.
The Study
The study set out to determine the causes of late-onset Alzheimer disease. It was assumed that the cause was a combination of genetic, environmental and lifestyle factors. Previous research had found a link between dichlorodiphenyldichloroethylene (DDE) in the body and Alzheimer disease. DDE is derived from DDT.
The researched involved looking at the serum levels of DDE and Alzeimer’s. 86 patients with Alzheimer’s were studied along with 79 control patients – healthy people with no sign of the disease.
The results of the study found that serum DDE levels were 3.8 times higher in the serum of those with Alzheimer’s. There was also an increase in patients with higher amounts of APOE ε3 allele (an apolipoprotein). Apolipoproteins are determined by diet, hormones, alcohol intake, drug use and other factors. APOE4 is also connected with many other conditions, including atherosclerosis, impaired cognitive function, ischemic cerebrovascular disease and sleep apnea.
The study concluded that: “Elevated serum DDE levels are associated with an increased risk for AD and carriers of an APOE4 ε4 allele may be more susceptible to the effects of DDE. Both DDT and DDE increase amyloid precursor protein levels, providing mechanistic plausibility for the association of DDE exposure with AD. Identifying people who have elevated levels of DDE and carry an APOE ε4 allele may lead to early identification of some cases of AD.”
The research was published in JAMA Neurology: “Elevated Serum Pesticide Levels and Risk for Alzheimer Disease” by Jason R. Richardson (and others). January 27, 2014. doi:10.1001/jamaneurol.2013.6030
DDT in Food
DDT is fat soluble and is therefore found in fatty foods such as dairy products (cheese, butter, milk, yogurt), meat (beef, lamb, pork, poultry) and eggs. It has also been seen in potatoes, deep water and shell fish.
It has a high environmental persistence (does not naturally decay on farmland and gets flushed into the water supply). It is also illegally used to increase yield in some countries. It is still found in soils in countries where DDT has been banned.
When was it banned?
- America – 1972
- UK – 1984
- Australia – 1987
- Germany – between 1972 and 1988
Map of Alzheimer’s prevalence
Further reading:
- DDT factsheet from the Pesticide Action Network UK
- WWF’s Efforts to Phase Out DDT
- History: the ban of Dichloro Diphenyl Trichloroethane (DDT) from Fair Companies.