Regular consumption of dietary components with anti-inflammatory properties is a promising strategy for management of inflammation-associated diseases. Oats, increasingly consumed in various forms such as oatmeal, granola, and oat milk, contain noteworthy anti-inflammatory elements. Here we review the functional components of oats: the glycolipid digalactosyldiacylglycerol (DGDG), estolides (esters of hydroxy fatty acids and fatty acids), and the oat-specific glycolipid DGDG-monoestolides. DGDG and estolides have garnered interest as functional lipids, and their physiological functions have been well documented. On the other hand, the biological functions of DGDG-monoestolides have been relatively unknown despite the fact that they contain DGDG and estolides as building blocks. Therefore, we have isolated a major DGDG-monoestolide molecular species from oats, analyzed its structure, and investigated its anti-inflammatory properties. Further in-depth knowledge of the functional components of oats, including the DGDG-monoestolides introduced in this review, will hopefully pave the way for wider utilization of oats as a functional food.

Vitamin K contributes to blood coagulation and bone homeostasis through post-translational modification (γ-carboxylation of glutamate) of vitamin K-dependent proteins. Vitamin K is distributed not only in the liver and bones but also in the brain and testis, where γ-carboxylation activity is low, but its role in these organs has not been well studied. Genome-wide gene expression analysis and subsequent studies have shown that vitamin K exerts anti-inflammatory effects by suppressing activation of the nuclear factor kappa B (NFκB) pathway. In addition, geranylgeraniol (GGOH), a side chain moiety of menaquinone-4, a type of vitamin K₂, also shows anti-inflammatory effects by suppressing the activation of interleukin-1 receptor-associated kinase 1 (IRAK1) in the NFκB signaling pathway. Additionally, vitamin K may suppress any reduction of testicular testosterone production through suppression of NFκB, which is activated during inflammation, and vitamin K and GGOH may also suppress inflammation in brain microglial cells.

Chronic inflammation in white adipose tissue associated with obesity has been shown to cause insulin resistance leading to diabetes. Recently, it has also become clear that chronic inflammation may exacerbate obesity by inhibiting the heat-producing capacity of brown and beige adipocytes, which are able to convert the energy obtained from fat consumption into heat. It has also been suggested that chronic inflammation in the intestinal tract may exacerbate postprandial hyperlipidemia, a risk factor for the development of atherosclerotic diseases. Thus, chronic inflammation in vivo causes abnormal lipid metabolism and is involved in the development of various lifestyle-related diseases. This implies that daily dietary intake of food-derived compounds with anti-inflammatory effects that suppress this chronic inflammation can be expected to improve abnormalities in lipid metabolism. In this article, we review the mechanism of lipid metabolism abnormalities caused by chronic inflammation and the effects of anti-inflammatory food components on lipid metabolism.

Chronic inflammation is an initial pathology common to lifestyle-related diseases, atherosclerosis, and bone diseases. In the adipose tissue of obese individuals, macrophages infiltrate hypertrophic adipocytes, resulting in excessive secretion of free fatty acids from adipocytes and inflammatory cytokines from macrophages. The paracrine interaction between adipocytes and macrophages contributes to chronic inflammation and fibrosis of adipose tissue, thereby inducing ectopic lipid accumulation in other organs and metabolic disorders such as insulin resistance. In addition, chronic inflammation leads to disruption of bone metabolism and increased bone resorption, in turn causing various bone diseases. On the other hand, polyphenols have been reported to exert an anti-inflammatory effect and are expected to contribute to disease prevention. This review outlines the role of chronic inflammation in the development and progression of various inflammatory diseases related to metabolic syndrome and locomotive syndrome and introduces the disease-preventive effects of polyphenols targeting chronic inflammation.

As chronic inflammation is known to lead to serious diseases such as cancer and diabetes, proper control of inflammatory responses is essential for maintenance of health. A wide variety of food-derived low-molecular-weight compounds is known to possess bioactivities such as anti-inflammatory, antioxidant, and anti-tumor activity. Long experience has shown that certain foods have health benefits, but the molecular mechanisms by which food-derived low-molecular-weight compounds exert their bioactivity have remained unclear. By focusing on the electrophilic activity of food-derived compounds, we have identified several proteins as target molecules for the anti-inflammatory activity of food-derived low-molecular-weight compounds. Here we review the anti-inflammatory activity of iberin from cabbage and curcumin from turmeric.