Adding a little spice to your diet might help increase your metabolism and help ward off chronic diseases such as diabetes and heart disease, authors of a small but intriguing study reported August 1 in the Journal of Nutrition. Men in the study who added antioxidant-rich spices to their meals experienced several metabolic benefits, including lowered insulin and triglyceride levels.
Insulin, the hormone that helps controls blood sugar levels, is often higher in people who have a condition called “pre-diabetes” and are more likely to develop diabetes. Triglycerides are a type of “bad fat” found in the blood. Triglycerides have been linked to heart and blood vessel disease.
West was interested in the spices because of their antioxidant effects. Antioxidents act as “scavengers,” taking up charged particles called “free radicals.” Left unchecked, free radicals can cause widespread damage to the body. While it’s been demonstrated that spices contain large amounts of antioxidants, few investigators have measured antioxidant effects and the time frame in which they occur in human subjects.
West’s team enrolled six healthy-but-overweight men ages 30 to 65 in the study. The researchers fed the men a high-calorie, high-fat, spice-free meal, which consisted of coconut chicken, a white rice dish, cheese bread, and a dessert biscuit. The meal was a diet-buster at 1200 calories.
One week later, the researchers had the men eat the same meal. However, this time the meal was well seasoned with several spices known for their antioxidant powers, including turmeric, cinnamon, garlic powder, rosemary, oregano, and paprika. All told, 14 grams of antioxidant-rich spices were added to the meal – about the same amount of antioxidants as 1.4 ounces of dark chocolate or five ounces of red wine, according to the investigators.
The investigators took blood samples from the men before each meal and then every 30 minutes afterwards until 3.5 hours had passed. After the spicy meal, they found a significant difference in the men’s insulin and triglyceride levels. Insulin levels were 21 percent lower than after the non-spicy meal, while triglycerides were 31 percent lower. Glucose was not affected.
Antioxidant activity appeared to increase significantly after the spicy meal. Ferric reducing antioxidant power, a marker of antioxidant activity in the blood, doubled. The researchers also tested the blood’s oxygen radical absorbance capacity (ORAC). ORAC is another way of measuring antioxidant capacity. Hydrophilic (“water-loving”) ORAC levels were 13 percent higher at all times measured, although total and lipophilic (“fat-loving”) ORAC levels remained the same.
These findings led study lead author Sheila West, Ph.D. of Penn State University to note in a statement that “Antioxidants like spices [sic] may be important in reducing oxidative stress and thus reducing the risk of chronic disease.”
Several mechanisms might be at play, hypothesized researchers. The spice mixture might have caused the stomach to empty more slowly and reduced secretion of pancreatic lipase – the chemical secreted by the pancreas to break down fats. Findings of decreased insulin response may have been due to the high amount of polyphenols, a type of antioxidant found in the spices. Previous studies had suggested that cinnamon might improve insulin sensitivity.
The researchers concluded that “The incorporation of spices into the diet might help to normalize postprandial insulin and TG [triglycerides] and enhance antioxidant defenses.”
Still, these results should be taken with a grain of salt, pepper, and a dash of paprika. The study had some significant limitations. The study was extremely small, involving only six men. The researchers noted that further studies are needed in larger, more diverse groups of people. Likewise, they wrote, the effects of individual spices need to be teased out.
In addition, the study was partly funded by the McCormick Science Institute, the research arm of spice distributor McCormick & Co. The Institute, although research-driven, is focused on health benefits – not drawbacks – of spices. Its “mission is to support scientific research and disseminate information on the health benefits of culinary herbs and spices to all stakeholders including consumers and health professionals.” Other funding came from a neutral source, the National Institutes of Health.