Dr Downing is President of the British Society for Ecological Medicine and was for 20 years Editor of the Journal of Nutritional and Environmental Medicine. He serves on the Editorial Board of the Orthomolecular News Service.
His 1988 book Daylight Robbery pioneered our understanding of how vital sunlight and vitamin D are for health. His book The Vitamin Cure for Allergies was released in 2010, and The Vitamin Cure for Digestive Disorders in 2013.
He has particular interests in membrane lipids and lipid therapy, in mitochondrial dysfunction, in environmental toxic effects, and in sunlight and vitamin D.