Protective Effects of Sulforaphane Preventing Inflammation and Oxidative Stress to Enhance Metabolic Health: A Narrative Review

Abstract

The worldwide obesity epidemic has led to a drastic increase in diabetes and cardiovascular disease in younger generations. Further, maintaining metabolic health during aging is frequently a challenge due to poor diets and decreased mobility. In this setting, bioactive nutrients that are naturally occurring antioxidants, such as sulforaphane (SFN), are of high nutritional interest. SFN, a bioactive compound that is present in cruciferous vegetables, is a molecule that protects cells from cytotoxic damage and mitigates oxidative stress, protecting against disease. It exerts its action through the activation of the transcription factor nuclear factor erythroid 2-related factor 2 (Nrf2). Many studies have been performed in animals and humans to evaluate its effects on cancer, brain health, and neurodegenerative disorders. However, fewer clinical studies have been performed to evaluate its effects on insulin resistance and the development of type 2 diabetes mellitus (T2DM) across the lifespan. Given that, in some parts of the world, particularly in Europe, the population is growing older at a significant rate, it is crucial to promote healthy habits (healthy foods, dietary pattern, precision nutrition, and physical activity) from an early stage in life and across the lifespan to avoid debilitating health conditions occurring during adulthood and aging. Thus, in this narrative review, we discuss the protective effects of SFN supplementation on inflammatory and oxidative stress pathways and relate them to metabolic disease.

Keywords: Nrf2; healthy aging; inflammation and oxidative stress; metabolic diseases; metabolic syndrome; nutraceutical; sulforaphane.

Figure 1

The umbrella protective effect of SFN in immune/metabolic aging. During the aging process, Nrf2 activity decreases, resulting in an inefficient cellular stress response. SFN acts on this axis by the direct induction of Nrf2-ARE binding. Simultaneously, inflammation is also a hallmark of aging. Levels of inflammation are increased in the elderly, and this is associated with a poor quality of the aging process. The action of SFN relies also on the inhibition of TLR4 oligomerization resulting in a decreased activation of the NF-kB pathway and the pro-inflammatory profile of the cell. SFN: sulforaphane; Nrf2: nuclear factor-erythroid factor 2-related factor 2; Keap1: Kelch-like ECH-associated protein 1; ARE: antioxidant response element; OH-1: Heme oxygenase-1; NQO-1: NADPH quinone oxidoreductase enzyme; SOD-1: superoxide dismutase; TLR4: Toll-like receptor; Nf-κB: nuclear factor kappa-light-chain-enhancer of activated B cells; TNF-a: tumor necrosis factor; IL-6: interleukin 6; IL-1b: interleukin-1b.