Why Spices are Special
The human pursuit of spices has helped to create the world (and America) as we know it today. Hundreds of years ago, merchants from Europe traveled by land and sea to transport exotic and expensive plants such as cinnamon, rosemary, nutmeg and turmeric from Asia. But when the Ottoman Empire restricted Europe’s spice routes to Asia in the 1400s, explorers such as Christopher Columbus looked for alternate routes to India and instead stumbled on our glorious land. It’s not a far stretch to thank cinnamon for our providence.
Spices hold a special place in human existence that we are just starting to understand. Sure, they are prized to provide bold and unique flavors, aromas and colors to otherwise bland foods. But many don’t know the hidden story: before the invention of refrigeration, spices’ underlying bioactivity, in the form of potent and diverse antioxidant and antimicrobial food-preserving properties, helped to prevent sickness and contagion caused by food spoilage. Thus, spices carried a magical aura for those who demanded them, and at the same time, they provided a livelihood for many generations of farmers, harvesters and suppliers.
Today, our interest in spices has shifted to the scientific study of their health benefits, to see if they can help us live healthier lives. On a molecular level, the chemical properties that make spices great flavorings, colorings and food preservatives are closely linked to the properties which help to promote human health. Polyphenols, carotenoids and terpenoids are all highly bioactive and health-supporting classes of compounds common to many spices, and are the focus of thousands of medical research studies.
Consuming enough of these active compounds to make a difference in our health can be tough through food alone. The mantra of many is that a diet with a diversity of spices can help us live longer, but no one is suggesting that fried chicken made with 14 of them is a health food (yet!). And while variety may be the “spice of life,” research suggests a variety of spices added to food can lead to a tendency to overeat.1 Likewise, consumer health media recommendations to sprinkle some cinnamon on toast or add a pinch of turmeric powder to curry may be naïve to some key underlying practical and scientific caveats such as compliance, dose response and opposing effects.
For instance, a clinically significant effective dose of cinnamon powder often recommended for managing blood sugar is a teaspoon or more—quite a “cinnamon challenge” for the palate and the stomach. Impurities that can be found in cinnamon powder, such as added sulfites and naturally occurring coumarin can tip the opposing-effects equation in the wrong direction, especially when doses are in baking measurements. On the other hand, science has validated the efficacy of concentrated, purified extracts, both from Chinese cinnamon (cassia) as well as “true” cinnamon (Cinnamomum verum syn. zeylanicum). Both the “whole food” and the scientific approaches have merits, but the second seems to garner increasingly more credibility among top medical experts.
In another example, four-week supplementation with the amount of straight turmeric powder contained in a strong curry (2.8 g) did not improve oxidative stress, inflammation or global metabolic profile in overweight women.2 But in another study just published on a purified, brain-optimized form of curcumin, just 80 mg of the potent turmeric active consumed daily for four weeks led to significant improvements in measures of short-term memory, attention and mental energy.3
On the other side of getting enough of the active compound absorbed to make a difference is the argument for moderation. Again, we seek to know what the relationship is between the amount of dose and the health benefit observed, and no two natural compounds are exactly alike in this way. The scientific results can be hard to predict. For example, in cell culture experiments where one biological mechanism is isolated, it is common and desirable to see the response increase as the dose increases. But for human trials, more does not always mean better. In one example, daily low dose (750 mg) of rosemary marginally improved cognitive function in elderly adults, but the higher 6-gram dose did not.4
For some spices, their aroma and impact on the brain through our nose is the main source of impact on health. A fair number of well-designed studies have shown positive results with herb and spice aromatherapy on various cognitive-related measures. One study found lavender or rosemary aromatherapy improved relaxation and test scores in nervous nursing students.5 However, rosemary consumed in a capsule form—while wearing a nose clip to block effects of the aroma—did not induce consistent short-term improvements in cognitive function in young adults.6
Topical applications of spices have been used in traditional medicine like Ayurveda for hundreds of years, with turmeric being well proven and used by allopathic physicians for its wound-healing capabilities. The bioactivities of spices that preserve food also promote health in ways that are well known mechanistically, but in a clinical-sense are just now emerging. For example, in a 2014 study, an ointment containing cinnamon was effective at reducing pain after childbirth.7 In another study, a topical application of black pepper essential oil improved vein visibility for IV insertion better than the standard of care.8 This study did not measure whether sneezing increased, although the essential oil used in the study would probably have improved dinner too.
The potential of spices in human health and wellness is vast, and with sound science, more is learned every day about how and why spices can be beneficial.
References:
1. Jones JB et al. “A randomized trial on the effects of flavorings on the health benefits of daily peanut consumption.” Am J Clin Nutr. 2014 Mar;99(3):490-6. DOI: 10.3945/ajcn.113.069401.
2. Nieman DC et al. “Influence of red pepper spice and turmeric on inflammation and oxidative stress biomarkers in overweight females: a metabolomics approach.” Plant Foods Hum Nutr. 2012 Dec;67(4):415-21. DOI: 10.1007/s11130-012-0325-x.
3. Cox KH, Pipingas A, Scholey AB. “Investigation of the effects of solid lipid curcumin on cognition and mood in a healthy older population.” J Psychopharmacol. 2014 Oct 2. PII: 0269881114552744.
4. Pengelly A et al. “Short-term study on the effects of rosemary on cognitive function in an elderly population.” J Med Food. 2012 Jan;15(1):10-7. DOI: 10.1089/jmf.2011.0005..
5. McCaffrey R, Thomas DJ, Kinzelman AO. “The effects of lavender and rosemary essential oils on test-taking anxiety among graduate nursing students.” Holist Nurs Pract. 2009 Mar-Apr;23(2):88-93. DOI: 10.1097/HNP.0b013e3181a110aa.
6. Lindheimer JB, Loy BD, O’Connor PJ. “Short-term effects of black pepper (Piper nigrum) and rosemary (Rosmarinus officinalis and Rosmarinus eriocalyx) on sustained attention and on energy and fatigue mood states in young adults with low energy.” J Med Food. 2013 Aug;16(8):765-71. DOI: 10.1089/jmf.2012.0216.
7. Mohammadi A et al. “Effects of cinnamon on perineal pain and healing of episiotomy: a randomized placebo-controlled trial.” J Integr Med. 2014 Jul;12(4):359-66. DOI: 10.1016/S2095-4964(14)60025-X.
8. Kristiniak S et al. “Black pepper essential oil to enhance intravenous catheter insertion in patients with poor vein visibility: a controlled study.” J Altern Complement Med. 2012 Nov;18(11):1003-7. DOI: 10.1089/acm.2012.0106.
By: Blake Ebersole
This article was first published in Natural Products Insider, December 2014
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