Are Beans Allowed on Anti-Inflammatory Diets?
Acute inflammation is a vital part of the body's immune response. When you catch a cold or cut yourself, your immune system switches into combat mode. Infection or injury trigger a chain of events called the inflammatory cascade which begins when pro-inflammatory hormones in your body call out for your white blood cells to come and clear out infection and damaged tissue.
But sometimes this mechanism won't shut off, even if you aren't in imminent danger, resulting in chronic inflammation. Also known as systemic or low-grade inflammation, this long-term inflammation has been linked to a variety of ailments, ranging from heart disease and rheumatoid arthritis to asthma and psoriasis. Chronic inflammation is often associated with poor dietary habits, which has made it of interest to nutritionists and led to a surge in interest in anti-inflammatory diet plans.
In a nutshell, anti-inflammatory diets work by restricting foods with pro-inflammatory properties and by increasing the intake of foods that contain anti-inflammatory nutrients and phytochemicals. If you are about to embark on an anti-inflammatory diet, you might be wondering whether a specific food is allowed on your diet plan. In case you are unsure about beans, here's what you should know:
Lab Studies Show Beans Have Strong Anti-Inflammatory Properties
In an intriguing study published in The Journal of Agricultural and Food Chemistry, Canadian researchers analyzed four types of beans (black, Great Northern, pink and pinto) and found that the hull extracts were able to inhibit the pro-inflammatory mediators COX 1 and COX 2 (1). This effect was attributed to their antioxidant properties and was most pronounced in black beans which contained the highest levels of flavonols and anthocyanins among the tested cultivars. In fact, an acetone extract of black bean hull had even stronger COX-inhibiting effects than aspirin. The researchers concluded that their findings raise the possibility that the use of antioxidant-rich bean hulls in foods might help protect against some diseases associated with chronic inflammation.
But, turns out, the antioxidant activity may not be the only means by which beans may help fight inflammation. In another laboratory study, researchers assessed the antioxidant capacity and anti-inflammatory properties of protein hydrolysates derived from two bean cultivars, Negro 8025 and Pinto Durango. Published in the August 2011 issue of the journal Food Chemistry, this study found that the hydrolysates of both bean varieties inhibited inflammation by modulating the NF-κB pathway. (2) The NF-κB pathway is considered a prototypical pro-inflammatory signaling pathway, largely based on the role of the NF-κB protein complex plays in the expression of pro-inflammatory genes such as cytokines, chemokines and adhesion molecules (3).
Autoimmune Patients, Take Note
Although the results of laboratory studies described above have been promising, research investigating the anti-inflammatory effects of beans in people suffering from inflammatory diseases is scanty. What's more, some experts have hypothesized that beans might even cause rather than curb inflammation in people who suffer from an autoimmune disease. This theory is based, to a large extent, on the high levels of saponins and lectins found in dry beans.
Saponins and lectins are anti-nutrients that protect plants against insect and microbe attacks by dissolving the cell membranes of these potential predators. But some experts believe that the types of saponins and lectins found in beans may be harmful not only to insects and microbes but also to people due to their ability to interact with the cells that line the gut. This may be particularly problematic for autoimmune patients many of whom are believed to suffer from, or have an increased risk of developing, a condition called "leaky gut". In healthy people, the gut lining acts as a barrier that undigested and foreign material from leaking into the bloodstream, but in people with a leaky gut, the lining of the gut wall is damaged and these unwanted substances can escape into the bloodstream where they can agitate the immune system and trigger inflammatory reactions.
That said, the evidence supporting claims that beans might be bad for autoimmune patients is primarily based on test tube and animal studies investigating the effects of specific types of saponins and lectins, plus some anecdotal reports. So, more research is definitely in order before any definite conclusions can be made about the proposed pro-inflammatory effects of beans in autoimmune patients.
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