Nutrients for Reducing Oxidative Stress

by Jordan Taffet, Dietetic Intern, M.S. Candidate

Oxidative stress is defined as an imbalance in the body between reactive oxygen species (ROS) and the body’s ability to detoxify these ROS and to repair damage. We all produce ROS naturally and, if the body is functioning optimally, we can fight off these ROS through neutralization by antioxidants. However, when stress levels are high, when we are over- exposed to oxidation in our environment, and/or in the case of certain disease states, the body may not be able to fend off damage done by ROS. Nutrition is one factor that can be optimized in order to assist the body with fighting against oxidation and internal damage.

Nutrients to Focus on

In general, antioxidants are the most powerful nutrition tool for fighting against ROS. We can consume antioxidants through foods such as: fruits, vegetables, nuts, seeds, and dark chocolate. Research shows that consuming antioxidants is an effective way to fight off ROS, and that combining antioxidant intake with a plant-based or Mediterranean diet has been proven to be most effective (1). A Mediterranean diet emphasizes intake of fruits, vegetables, fish, nuts/seeds, spices, herbs, and healthy oils, while minimizing the intake of saturated fats, sugars, and refined carbohydrates. This has been shown to be protective of oxidative stress levels, as the promoted food groups enhance antioxidant defense and improve overall lipid profiles and LDL oxidation within the body (2). In addition, regular intake of these foods often leads to a decrease in BMI, better insulin sensitivity and blood pressure, which are also allies in fighting against oxidative stress. One study found that, in addition to the Mediterranean diet, the Okinawa diet is also effective at reducing oxidative stress (3). This is due to the Okinawa’s higher intake of green, yellow, and root vegetables, soybeans, polyunsaturated fatty acids, omega-3 fatty acids, and phytonutrients. These compounds reduce overall risk for oxidative stress, and as a result, risk for developing several disease states.

Another nutrient group for minimizing oxidative stress is polyphenols. Polyphenols are organic chemicals found in plant-based foods that are packed with antioxidants and health-enhancing properties. Food sources of polyphenols are similar to those for antioxidants, as polyphenols are found in: fruits, vegetables, whole grains, nuts, seeds, legumes, coffee, tea, red wine, and healthy fats (such as virgin olive oil and sesame seed oil). Polyphenols can also be found in spices and seasonings such as: cacao powder, saffron, oregano, rosemary and cloves. Research indicates that consumption of polyphenols can reduce oxidation within the body by inhibiting proinflammatory cytokines and by inducing mitochondrial biogenesis in skeletal muscle and in the brain (2).

Focusing on increasing frequency of more plant-based, whole-food meals would be a dependable way to reduce oxidative stress within the body. The components and micronutrients consumed in a plant-based diet target inflammation by reducing inflammatory pathways and key players in these pathways. Research shows that plant-based diet followers have lower levels of oxidative stress and micro-inflammation compared to meat eaters due to the reduction in trimethylamine-N-oxide (TMAO), reduction of overall LDL oxidation levels and reduction of risk for atherosclerosis (1).

One supplement that may be worthwhile for strictly plant-based eaters is conjugated linoleic acid (CLA). CLA is a fatty acid found mostly in meat and animal-based products and has been shown to reduce oxidative stress within the body. This is thought to be due to its antioxidant activity and ability to induct antioxidant enzymes while decreasing lipid peroxidation (4). Because further research is warranted for investing the link between CLA and oxidative stress, there is no need to worry too much about CLA levels for now.

Lastly, there is evidence to suggest that caloric restriction is protective of accumulating levels of oxidative stress. A hypocaloric diet has been shown to reduce oxidative stress within the body by improving the body’s use of free fatty acids and adipose tissues, leading to a reduction in fatty tissue and ROS (5). This is thought to be due to, in part, the concept of hormesis, which is the beneficial actions that occur as a response to a low intensity stressor. This suggests that it is important for our bodies to be able to inherently fight off stressors and that exposure to a low intensity stressor, such as caloric restriction, can actually improve the body’s ability to activate antioxidant enzymes and other proteins needed to adapt to stress (6).

Oxidative Stress and Brain Health

The topic of oxidative stress is especially important when it comes to brain health. For healthy individuals, optimizing brain health can be achieved by targeting oxidation. For those with neurodegenerative diseases and/or cognitive decline, minimizing oxidation within the brain is imperative. Our genetic variants and predispositions affect the way that the body is able to combat oxidative stress. Individual genetic variations in endogenous antioxidants may affect oxidative stress and overall development of disease. Research shows that these variations affect absorption, metabolism, distribution and elimination of exogenous antioxidants, which affects how antioxidants target cells (7). The diet can be modified in order to compensate for endogenous antioxidant enzymes and biomarkers of oxidative stress related to disease.

Oxidative damage within the brain naturally increases as we age. Research indicates that those with neurodegenerative diseases, such as Alzheimer’s Disease (AD), have more oxidative damage than those with healthy brains. This is thought to be due to the accumulation of substances that create plaques. The results from research studies are promising within this population, as we can target the mitochondria of AD patients with antioxidants and slow overall disease progression (8). Supplementing these patients with antioxidants has been shown to improve overall cognition and quality of life indicators.

In conclusion, oxidative stress is an inevitable process within the body that increases as we age. Through our genes, environment, and foods, we are constantly fighting off ROS and pro- inflammatory species. Targeting oxidative stress through nutrition is an efficient and implementable way to protect the body and the brain and is crucial for those wanting to optimize cognitive functioning.

References:

1. Tuso P, Stoll SR, Li WW. A plant-based diet, atherogenesis, and coronary artery disease prevention. The Permanente journal. 2015;19(1):62-67.

2. Pingitore, A. et al. Exercise and oxidative stress: Potential effects of antioxidant dietary strategies in sports. Nutrition. 2015;31(7):916-922.

3. Willcox DC, Willcox BJ, Scapagnini G. Healthy aging diets other than the mediterranean: A focus on the okinawan diet. Mechanisms of Ageing and Development. 2014;136-137:148- 162.

4. Ebrahimi-Mameghani M, Jamali H, Mahdavi R, Kakaei F, Abedi R, Kabir-Mamdooh B. Conjugated linoleic acid improves glycemic response, lipid profile, and oxidative stress in obese patients with non-alcoholic fatty liver disease: A randomized controlled clinical trial. Croatian medical journal. 2016;57(4):331-341.

5. Gutiérrez L, García JR, Rincón MdJ, Ceballos GM, Olivares IM. Effect of a hypocaloric diet in the oxidative stress in obese subjects without prescription of exercise and antioxidants. Medicina clinica. 2015;145(1):1.

6. Poljsak B. Strategies for reducing or preventing the generation of oxidative stress. Oxidative medicine and cellular longevity. 2011;2011:194586-15.

7. Da Costa LA, Badawi A, El-Sohemy A. Nutrigenetics and modulation of oxidative stress. Annals of Nutrition and Metabolism. 2012;60(3):27-36.

8. Head E, Nukala VN, Fenoglio KA, Muggenburg BA, Cotman CW, Sullivan PG. Effects of age, dietary, and behavioral enrichment on brain mitochondria in a canine model of human aging. Experimental Neurology. 2009;220(1):171-176.

9. Trapp D, Knez W, Sinclair W. Could a vegetarian diet reduce exercise-induced oxidative stress? A review of the literature. Journal of Sports Sciences. 2010;28(12):1261- 1268.

10. Garrido M, Terrón MP, Rodríguez AB. Chrononutrition against oxidative stress in aging. Oxidative medicine and cellular longevity. 2013;2013:729804-9.