Role of dietary spices in modulating inflammation and oxidative stress

Obesity-induced oxidative stress and inflammation are strongly associated with cardiovascular disease (CVD). Accumulating evidence suggests that spices can help lower oxidative stress and inflammation, which may reduce the risk of CVD. The objective of the current review was to comprehensively summarize the findings from clinical studies that examined the antioxidative and/or antiinflammatory effects of popular and widely used spices in the United States. A systematic literature search was conducted in CINAHL, Cochrane Library, and PubMed to identify studies that investigated the effect of selected spices on markers of oxidative stress and inflammation in humans. A total of 99 eligible clinical studies were identified that examined the antioxidative and/or antiinflammatory effect of consuming Capsicum (n=2), cardamom (n=4), cinnamon (n=13), cumin (n=5), dill (n=1), fenugreek (n=4), garlic (n=20), ginger (n=21), onion (n=3), oregano (n=2), parsley (n=1), sage (n=1), sesame (n=12), turmeric (n=7), and spice blend (n=7). We found numerous studies that reported an antioxidative effect of consuming cinnamon (n=4), garlic (n=10), ginger (n=5), and sesame (n=11) and an antiinflammatory effect of consuming cinnamon (n=6), garlic (n=5), ginger (n=14), and turmeric (n=5). Few of the included studies report an antioxidative effect of consuming Capsicum (n=1), cardamom (n=2), cumin (n=3), dill (n=1), fenugreek (n=1), onion (n=2), oregano (n=1), parsley (n=1), sage (n=1), and turmeric (n=1) and an antiinflammatory effect of consuming cardamom (n=2), cumin (n=1), fenugreek (n=2), oregano (n=1), and sesame (n=2). There are no clinical studies to date that demonstrate an antiinflammatory effect of consuming Capsicum, dill, onion, parsley, and sage. In addition, several clinical studies report an antioxidative (n=2) and an antiinflammatory (n=3) effect of consuming a blend of spices given as dietary supplements or delivered in a meal. Combined, these findings suggest an antioxidative and antiinflammatory effect of several commonly used spices.