Tomatoes, peppers, potatoes, and eggplant belong to the same botanical family Solanaceae which is also commonly known as the nightshades. They produce an alkaloid compound called solanine which acts as a nerve poison and serves to defend the plants against pests. Diet has been noted to be linked to circulating inflammation markers through research.
Do night shades cause inflammation?
- Tomato: Lycopene found in tomato is noted to down-regulate the inflammatory response.
One of the possible mechanisms for its protective activities is by down-regulation of the inflammatory response. That includes the inhibition of pivotal pro-inflammatory mediators, such as the reduction of reactive oxygen species, the inhibition of synthesis and release of pro-inflammatory cytokines, changes in the expression of cyclooxygenase and lipoxygenase, modifications of eicosanoid synthesis, and modulation of signal transduction pathways, including that of the inducible nitric oxide synthase via its inhibitory effects on Nuclear Factor-kB (NF-kB), Activated protein-1 (AP-1) and mitogen-activated protein kinase (MAPK) signaling. Recent data suggest that lycopene also exhibits anti-inflammatory activity through induction of programmed cell death in activated immune cells.
Vitamin C present in tomato also may have a beneficial effect on inflammation.
Consumption of fruit and vegetables, in general, has been inversely associated with CRP levels and other biomarkers of inflammation. In two small intervention trials, consumption of tomato juice or a tomato-based soft drink was associated with decreased markers of inflammation, but other dietary components of tomatoes besides lycopene, such as vitamin C, may in part be responsible for any beneficial effects on inflammatory processes.
- Peppers: Research shows different varieties of pepper such as Capsicum annuum and Capsicum baccatum contain potential anti-inflammatory compounds which could be tested as future drug candidates for inflammation-related diseases.
Capsicum annuum L., a fruit plant from tropical and subtropical regions, contains a range of essential nutrients and bioactive compounds which are known to exhibit a range of bioactivities including free radical scavenging (antioxidant), antimicrobial, antiviral, anti-inflammatory and anticancer. This review aims to give a comprehensive overview of the literature published on pharmacological behaviours of C. annuum L.
- Potato: Pigmented potato consumption is noted to reduce inflammation in healthy adult males. Also potato peel extracts are noted to exhibit anti-inflammatory effects in vitro.
In 2008 and 2009, we received funding from the Maine Agricultural Center to look at a number of differently colored potatoes for total antioxidant activity in the tuber, tuber flesh, and tuber skin. We compared potatoes from tan-skinned, white-fleshed potatoes such as Kennebec, to purple-skinned, purple-fleshed potatoes like Purple Majesty, and we found significant differences in total antioxidant activity among these potatoes. Generally, the more color there was in the potato skin and flesh, the higher the total antioxidant activity. We found more than twice the antioxidant activity in purple potatoes than we found in tan-skinned, white-fleshed potatoes.
However, the above research should be noted with caution as these findings should not be applied to consumption of French fries and chips which may be the most popular way of consuming potatoes around the world. Chronic ingestion of acrylamide-containing potato products such as fries, chips and cereals is known to induce a proinflammatory state which is a risk factor for progression of atherosclerosis.
It has been shown also that acrylamide increases the production of reactive oxygen species in isolated human monocyte-macrophages in vitro and decreases the cellular glutathione concentration.
Eggplant: Solanum melongena (egg plant) is known to contain a high amount of hydroxycinnamic acid conjugates and hydroxycinnamic acid derivatives from corn are noted to have anti-inflammatory activity. However it is not clearly known or tested whether those hydroxycinnamic acid conjugates from egg plants cause anti-inflammatory activity in humans. There are no published research studies testing the effects of eggplant on inflammation in humans.
Mushrooms: The anti-inflammatory effects of edible mushrooms are well researched and the findings are present here and here.
Whole mushrooms have a number of components that are potentially immuno-modulatory. Whether the increase is an effect of known immuno-modulatory nutrient components or as a result of bacteria like the psuedomonads that are associated with mushroom cultivation is not known.
- Current research evidence does not confirm a definitive link for causation between nightshades and inflammation.
For now, there just is not enough quality research to support a link between nightshades and arthritis or other inflammatory conditions. The fruit of these plants have lots of antioxidants that should, if anything, reduce inflammation.
- Certain people might have sensitivity to certain vegetables or fruits based on their body condition or genetics, but this is not a common occurence applied to a general population.
Bottom Line: People with arthritis may benefit from nightshades, although some people may have sensitivities to certain vegetables.
- Apart from diet, moderate and regular physical activity is known to decrease both acute and chronic inflammation.
Animal and human studies have found that various forms of physical activity decrease both acute and chronic inflammation, as measured by reductions in CRP and certain pro-inflammatory cytokines. Moreover, regular physical activity is important in reducing one’s risk for obesity and chronic diseases associated with inflammation. However, excessive exercise can increase systemic inflammation. For example, overtraining syndrome in athletes is associated with systemic inflammation and suppressed immune function