Starving from within

Stewing in our chemical effluent

Beriberi is a deficiency of vitamin B1, also known as thiamine. It used to be a big problem for many human populations, especially those on long sea journeys, but these days is easily solved through fortified foodstuffs such as cereals.

However, an alarming deficiency in B1 is occurring in fish and birds. This was first detected in Baltic seabirds in the 1980s who were so deficient in thiamine that they were unable to fold their wings, to sing, or for their legs to hold their own weight.

Thiamine deficiency has since been reported in multiple species and food webs, from giant moose to little minnows, in particular places and periods. In affected populations it can impair survival and reproduction, although the evidence does not support describing it as a universal, single-cause collapse of the entire food chain.

The causes remain uncertain. Its appearance across disparate species may reflect several mechanisms, including changes in food-web transfer, dietary thiamine availability, pollutants, or combinations of these factors.

Research continues into the causes. The ecological consequences could be serious if widespread deficiencies persist without being understood and mitigated.

One hypothesis worth investigating is a role for endocrine-disrupting chemicals. There are reported interactions between bis(2-ethylhexyl) phthalate (DEHP) and thiamine metabolism in the liver, but this does not establish DEHP as the cause of wildlife deficiency.

Another potential factor is pollution runoff. Thiamine contains sulfur, but the ecological relationship between mercury exposure and wildlife thiamine deficiency remains uncertain. Coal combustion remains an important anthropogenic source of mercury pollution, whose effects can persist long after a plant closes.

Our global society should invest further in properly selected and monitored water treatment, including activated carbon for many organic pollutants and membrane or other methods where appropriate. No single filter removes every endocrine disruptor and heavy metal, but cleaner waterways protect our species and others.