At the Diet and Optimum Health Conference, the seventh Linus Pauling Institute Prize for Health Research was presented to Dr. Helmut Sies of Heinrich Heine University Düsseldorf in Germany. The Prize, consisting of a medal and $25,000, recognizes innovation and excellence in research on the roles of micronutrients (vitamins and minerals) and phytochemicals in promoting optimum health and preventing or treating disease and successful efforts to disseminate knowledge to enhance public health. The prize recognized Dr. Sies’ important discoveries relating to the antioxidant and skin protective effect of the carotenoid lycopene, the role of flavanols in cocoa on vascular function, and the biochemistry and antioxidant function of selenium-containing proteins. In 1985, Dr. Sies coined the term “oxidative stress,” which refers to an imbalance between antioxidants and reactive oxygen species/oxidants that can damage biomolecules like DNA, proteins, fatty acids, and cell membranes. As one prominent researcher noted in his letter of support for Dr. Sies’ nomination, “Dr. Sies has contributed so heavily to the phytochemical/nutrient health promotion and oxidative stress/antioxidant areas that he is considered as both a pioneer and a giant in all these fields.”
Dr. Sies received his medical degree from the University of Münich and held faculty positions at the University of Münich before being appointed Professor and Chairman in the Department of Physiological Chemistry at the University of Düsseldorf. He has also served as an adjunct Professor in the Department of Molecular Pharmacology and Toxicology at the University of Southern California since 2000. He is the author of over 500 scientific papers and over 25 books.
In his lecture after accepting the award, Dr. Sies discussed his research interests in depth, including the topic of oxidative stress. Reactive oxygen species (ROS)—molecules with unpaired electrons that “steal” electrons from other molecules, thereby oxidizing them—can be deleterious or beneficial, depending on the context. For example, tadpole tail regeneration after amputation requires ROS. Plants synthesize antioxidants like vitamin C and carotenoids to protect against oxidative damage from the sun’s ultraviolet light.
Dr. Sies mentioned that Albert Szent-Györgyi, who won the 1937 Nobel Prize in Physiology or Medicine for work on vitamin C and oxidation reactions, originally proposed the term “ignose” for vitamin C, underscoring some ignorance about the molecule, then “godnose,” followed by a compromise with “hexuronic acid,” which turned out to be incorrect, and finally, with Haworth, “ascorbic acid.”
Singlet oxygen, an ROS produced in plants by the action of chlorophyll and also present in the human body, is most effectively quenched by the carotenoid lycopene, which Dr. Sies has studied for many years. He carried out seminal research on the absorption of lycopene, its biochemistry, and its health effects, particularly its protection against UV-induced erythema or sunburn.
Arteries expand and contract depending on many factors, and good arterial dilation is associated with normal blood flow. Arterial dilation is impaired after consuming a high-fat meal that causes oxidative stress and the generation of oxidized fats, which can contribute to the atherosclerotic process. Dr. Sies noted that consumption of red wine attenuates the increase in lipid oxidation and that arterial dilation after such a high-fat meal can be improved by polyphenols, especially, as Dr. Sies’ research has demonstrated, flavanols in chocolate. Some of these flavanols, such as the catechins, are also found in tea. Cocoa can also attenuate UV-induced erythema. Dr. Sies referred to these beneficial effects of polyphenols as ”metabolic fine tuning.”
Selenium plays an important role in the function of the endogenous antioxidant glutathione. Dr. Sies has published much research on glutathione peroxidase, a selenium-containing enzyme that protects against oxidative damage. Glutathione peroxidase helps to get rid of hydrogen peroxide, which itself is not a free radical but can generate damaging free radicals when it reacts with some forms of metals like copper and iron to form hydroxyl radicals. In related work, Dr. Sies detected the “nitration” of proteins (“nitrative stress”) by nitrogen radicals implicated in cellular dysfunction and disease, including amyotrophic lateral sclerosis (ALS). Nutritionally adequate selenium may be helpful in the prevention of diabetes, but, as Dr. Sies has pointed out, excessive levels may actually increase the risk for diabetes.
Last updated October 2013