November/December 2024 Issue
Holistic Nutrition: Herbs and Spices’ Metabolic Impact
By Alexandria Hardy, RDN, LDN
Today’s Dietitian
Vol. 26 No. 9 P. 12
The Power of Culinary Doses in Everyday Cooking
Herbs and spices have been used for centuries to enhance the flavor, aroma, texture, and overall experience of food. They can transform a simple dish into something extraordinary, making them essential ingredients in every kitchen. But did you know they can also impart health benefits? This article explores the unique healthful attributes herbs and spices bring to the plate when consumed in a culinary dose.
Diversify Dishes and Beverages
Adding herbs and spices to meals can enhance food and drink thanks to their unique flavor profiles. Whether it’s a sprinkle of cinnamon in a cup of coffee or a dash of oregano in pasta sauce, herbs and spices can elevate the taste of the ingredients they’re combined with. In addition, each individual herb and spice boasts a distinctive flavor that can vary depending on whether they’re fresh or dried.
Herbs and spices are the aromatic, fresh, dried, or processed leaves and flowers of herbaceous plants. Technically speaking, herbs are classified as the fresh part of the plant (think leaves), while spices are considered the dried, aromatic portion of the plant (stalk, root, seeds, and fruits).1 This is why a grocery store might sell fresh bundles of cilantro (typically the leaves and stalk) but jars of dried coriander, which are the seeds of the same plant. Spices and herbs may have different smells, tastes, and flavors, though herbs tend to have a higher or more concentrated dose of health-boosting benefits.2
Global Varieties
Nearly all of the recognizable herbs and spices that are used today come from the Middle East, Asia, and the Mediterranean; many have been in use since ancient times.1 Basil, oregano, and rosemary are staples in Italian cuisine, perfect for pasta sauces and pizzas. Thyme, mint, and parsley are common in Mediterranean dishes like tabbouleh and hummus. Ginger, turmeric, and coriander are essential in many Asian recipes, from curries to stir-fries. Cinnamon and cardamom are originally found in the Indian subcontinent and can be used in both sweet and savory preparations, from chai to rubs and biryani.
Harvesting and Preservation
Fresh herbs can be picked from the garden or purchased from local markets. For the best flavor, select bunches that are vivid in appearance with aromatic leaves. To preserve freshness, it’s best to store herbs in the refrigerator or dry them for long-term use. Spices should be kept in a cool, dark place to maintain potency.
Medical Impact
Herbs and spices aren’t just flavor enhancers; they’re also packed with phytochemicals—natural compounds found in plants that have various health benefits. These phytochemicals have in vitro antioxidant, anti-inflammatory, and antimicrobial properties and are increasingly being studied for their in vivo health impact.1,3 In addition to their medicinal uses, they also have been used historically as food preservatives.1
What Is a Culinary Dose?
When discussing using herbs and spices in cooking, it’s essential to understand what a culinary dose is. A culinary dose refers to the amount of herbs or spices typically used in food preparation when considering the average American eating habits. Including herbs and spices in a meal can improve postprandial metabolic responses, especially as they relate to CVD, glycemic control, and oxidative stress.4
In a study published in the American Journal of Clinical Nutrition, a low-dose diet (also defined as low spice) was defined as 0.5 g/d, a moderate dose was defined as 3.3 g/d, and a high dose was defined as 6.6 g/d; all were based on 2,100 kcal diet.4 In teaspoons, this equates to the following:
• low dose: a pinch to 1/4 tsp;
• medium dose: 1/2 to 1 tsp; and
• high dose: more than 1 tsp.
Culinary Dose and Disease Risk
Herbs and spices can positively affect several health conditions when consumed at culinary doses, particularly metabolic syndrome (MetS). MetS is a cluster of conditions that increase the risk of heart disease, stroke, and type 2 diabetes.
A comprehensive search of the PubMed, Scopus, and Google Scholar databases was conducted to evaluate the existing clinical evidence on the use of culinary doses of commonly used herbs and spices.5 The review focused on trials that assessed health outcomes related to metabolic disorders in both healthy individuals and those with MetS or related conditions. From an initial pool of 1,738 papers, 142 relevant studies were identified that investigated the effects of black pepper, chili, cardamom, cinnamon, coriander, cumin, fennel, fenugreek, garlic, ginger, nigella seed, rosemary, sage, and turmeric.5 Some of the most potent and promising herbs and spices in terms of medicinal benefits postreview include cinnamon, ginger, and cardamom.5,6
In a series of studies, cinnamon didn’t significantly affect glycemic or inflammatory markers overall. However, it did improve menstrual cyclicality to a degree similar to metformin and increased serum antioxidant capacity.5,7 In people with poorly controlled type 2 diabetes, 2 g of cinnamon daily reduced HbA1c, systolic blood pressure, and diastolic blood pressure, although fasting blood glucose remained unchanged.5 In addition, cinnamon improved lipid profiles by reducing total cholesterol and LDL while increasing HDL levels.5
Ginger supplementation has been shown to offer several health benefits. It led to significant reductions in body weight, BMI, waist circumference, and appetite. It also improved fasting blood glucose, insulin levels, insulin sensitivity, and lipid profiles, including lower total cholesterol, triglycerides, and LDL, with an increase in HDL levels.8 Although it didn’t affect postprandial blood sugar, ginger decreased markers of insulin resistance and inflammation, such as C-reactive protein and prostaglandin.9 Ginger has also been shown to reduce thyroid symptoms and improve various domains of well-being, including weight gain, cold intolerance, and concentration issues.5
Meanwhile, cardamom was found to improve fatty liver grades, blood glucose levels, and lipid profiles.5,10,11 However, it didn’t significantly affect BMI, total cholesterol, or fasting blood glucose.5,12 The use of cardamom also resulted in a reduction in C-reactive protein and systolic blood pressure, along with an increase in serum nitric oxide. There were no changes observed in serum ADMA (a potential marker of CVD) or diastolic blood pressure.5
Incorporating Into the ‘Standard American Diet’
Incorporating herbs and spices into the standard American diet can be easy and delicious. Here are some practical tips to encourage clients to boost their intake of herbs and spices to an appropriate culinary dose, which is roughly 1 tsp dried herb or spice or 1 T fresh herbs. The general rule of thumb for converting or substituting dried herbs for fresh is a 1:3 ratio. For example, if you’re planning to use 1 tsp dried basil, you would need 1 T of fresh basil to impart the same benefits.
• Breakfast: Add a teaspoon of ground cinnamon and ginger to oatmeal, baked goods, or smoothies for a sweet, spicy kick.
• Lunch: Sprinkle 1 to 2 T of oregano and basil on salads, pasta, or sandwiches.
• Dinner: Use a teaspoon of ground garlic, rosemary, and thyme to season roasted vegetables or meats.
• Snacks: Mix 1/2 to 1 tsp of turmeric and black pepper into hummus or yogurt dips.
Study Limitations
While research on the health benefits of herbs and spices is promising, there are some limitations. Studies often focus on the effects of single herbs or spices instead of examining spice blends, which many individuals might use when cooking. Some of the samples are also extremely concentrated extract forms, which aren’t widely utilized in home cooking; there’s also a prevalence of dried, ground herbs and spices studied as opposed to fresh. Finally, the most widely studied populations are adults with acute or chronic illnesses, which can make the findings more difficult to generalize and disseminate to a broader population.
Future Research and Challenges
Future research should explore the impact of herbs and spices on the gut microbiota, as early studies suggest that herbs and spices can influence the gut microbiome and potentially lead to improved health outcomes. Many results are also dose dependent, which indicate that more research is necessary to determine the most efficacious dose as well as education on how to implement that dose.
One of the main challenges dietitians may face when discussing culinary doses of herbs and spices with their clients is a lack of confidence. Clinicians may not receive adequate culinary medicine training in their internships or on the job, which could lead to feelings of not being appropriately prepared.13 They may also need to coordinate care with other members of the interdisciplinary team to determine the potential effects of a culinary dose on medications.
Bottom Line
Herbs and spices are more than just flavor enhancers—they’re packed with health benefits. By developing an understanding of what culinary doses are and how to incorporate them into meals, dietitians can empower their clients to diversify their diets and support their overall health in a low-cost way that yields big results.13 From improving glycemic control to enhancing cardiometabolic health, the phytochemicals in herbs and spices make them a valuable addition to any kitchen. Keep experimenting with different combinations and enjoy the delicious results!
— Alexandria Hardy, RDN, LDN, is a nutrition educator and the owner of Pennsylvania Nutrition Services, an insurance-based private practice located in Lancaster, Pennsylvania.
References
1. Vázquez-Fresno R, Rosana ARR, Sajed T, Onookome-Okome T, Wishart NA, Wishart DS. Herbs and spices - biomarkers of intake based on human intervention studies – a systematic review. Genes Nutr. 2019;14:18.
2. Spence C. Coriander (cilantro): a most divisive herb. Int J Gastron Food Sci. 2023;33:100779.
3. Parham S, Kharazi AZ, Bakhsheshi-Rad HR, et al. Antioxidant, antimicrobial and antiviral properties of herbal materials. Antioxidants (Basel). 2020;9(12):1309.
4. Petersen KS, Davis KM, Rogers CJ, Proctor DN, West SG, Kris-Etherton PM. Herbs and spices at a relatively high culinary dosage improves 24-hour ambulatory blood pressure in adults at risk of cardiometabolic diseases: a randomized, crossover, controlled-feeding study. Am J Clin Nutr. 2021;114(6):1936-1948.
5. Mackonochie M, Rodriguez-Mateos A, Mills S, Rolfe V. A scoping review of the clinical evidence for the health benefits of culinary doses of herbs and spices for the prevention and treatment of metabolic syndrome. Nutrients. 2023;15(23):4867.
6. Jiang TA. Health benefits of culinary herbs and spices. J AOAC Int. 2019;12(2):395-410.
7. Davari M, Hashemi R, Mirmiran P, et al. Effects of cinnamon supplementation on expression of systemic inflammation factors, NF-kB and Sirtuin-1 (SIRT1) in type 2 diabetes: a randomized, double blind, and controlled clinical trial. Nutr J. 2020;19(1):1.
8. Arablou T, Aryaeian N, Valizadeh M, Sharifi F, Hosseini A, Djalali M. The effect of ginger consumption on glycemic status, lipid profile and some inflammatory markers in patients with type 2 diabetes mellitus. Int J Food Sci Nutr. 2014;65(4):515-520.
9. Ebrahimzadeh Attari V, Mahluji S, Asghari Jafarabadi M, Ostadrahimi A. Effects of supplementation with ginger (Zingiber officinale Roscoe) on serum glucose, lipid profile and oxidative stress in obese women: a randomized, placebo-controlled clinical trial. Pharm Sci. 2015;21(4):184-191.
10. Daneshi-Maskooni M, Keshavarz SA, Qorbani M, et al. Green cardamom supplementation improves serum irisin, glucose indices, and lipid profiles in overweight or obese non-alcoholic fatty liver disease patients: a double-blind randomized placebo-controlled clinical trial. BMC Complement Altern Med. 2019;19(1):59.
11. Kazemi S, Yaghooblou F, Siassi F, et al. Cardamom supplementation improves inflammatory and oxidative stress biomarkers in hyperlipidemic, overweight, and obese pre-diabetic women: a randomized double-blind clinical trial. J Sci Food Agric. 2017;97(15):5296-5301.
12. Aghasi M, Koohdani F, Qorbani M, et al. Beneficial effects of green cardamom on serum SIRT1, glycemic indices and triglyceride levels in patients with type 2 diabetes mellitus: a randomized double-blind placebo controlled clinical trial. J Sci Food Agric. 2019;99(8):3933-3940.
13. La Puma J. What is culinary medicine and what does it do? Popul Health Mang. 2016;19(1):1-3.