October 2019 Issue

Herbs and Spices: Rosemary
By Ginger Hultin, MS, RDN, CSO
Today’s Dietitian
Vol. 21, No. 10, P. 10

Discover this herb’s history, potential medical uses, and mouthwatering culinary possibilities.

These days, rosemary is best known for its role in recipes ranging from savory soups and stews to meats and side dishes to desserts, mocktails, and cocktails. However, since ancient times, it’s been used not only as a culinary herb but also a medicinal one.1

As consumer interest in natural remedies and holistic herbs continues to grow, dietitians’ knowledge of the culinary and potential medicinal uses of herbs such as rosemary will become increasingly important.

Traditional Uses
Rosemary (Rosmarinus officinalis) belongs to the Lamiaceae family, which also includes mint, basil, lavender, sage, and thyme. Rosemary is known for its small, firm, evergreen leaves that can be used fresh or dried in cooking as a seasoning, enhancing the flavor of food. Native to the Mediterranean region of the world, it’s used commonly in the traditional dishes of Portugal and the South of France.1

In addition to traditional culinary uses, rosemary leaves have been used in traditional medicine for their antibacterial, antidiabetic/blood sugar–lowering, and anti-inflammatory properties, as well as its analgesic, antioxidant, carminative (preventing/curing intestinal gas and bloating), and even antitumor effects.1,2

Ancient Greeks used rosemary to stimulate brain and memory function. There’s evidence that the Greek physician Dioscorides (40–90 AD) wrote about the health benefits of the herb, asserting that it could be used to soothe the stomach and improve memory.3 Rosemary also has been traditionally used topically to treat wounds and rashes, internally as a supplement or tincture to treat headache and improve circulation, and as a diuretic.1

Nutrient Breakdown
Because of how little is consumed in food in association with its use as a flavoring or seasoning, rosemary typically doesn’t provide many calories or nutrients. Rosemary contains only 1 kcal per teaspoon and trace amounts of fiber, iron, calcium, magnesium, potassium, zinc, folate, and vitamins A, B3, B6, and C.4

Potential Medicinal Compounds
The antioxidant phenolic compounds and terpenes in rosemary leaves likely are major contributors to rosemary’s purported benefits. Rosemary leaves contain antioxidant polyphenols, including apigenin, diosmin, luteolin, genkwanin, and phenolic acids.

Of rosemary’s phenolic acids, rosmarinic acid, chlorogenic acid, and caffeic acid have been most strongly linked to its potential medicinal uses. Rosemary leaves also contain terpenes such as epirosmanol, carnosol, carnosic acid, ursolic acid, and oleanolic acids.

Rosemary’s composition continues to be explored; as recently as 2014, five new compounds were identified in rosemary leaves.1 Some of these compounds have been researched for various properties and health benefits, including the following:

• Antitumor: The rosemary terpenes carnosic acid and carnosol in particular have exhibited antitumor activity in human cancer cells in vitro.1,2,5,6

• Antibacterial: Of the herbs in the Lamiaceae family, rosemary has exhibited the most potent anti-infectious activity in vitro, with studies showing activity against certain types of gram-positive and -negative bacteria.1

• Anti-inflammatory and analgesic: These properties have been exhibited in in vitro studies that have evaluated the effects of rosemary polyphenols and terpenes on inflammatory proteins interleukin 1 beta, interleukin 6, tumor necrosis factor alpha, and cyclooxygenase 1 and 2, among others.1

• Cognitive health: There have been small clinical trials on the benefits of rosemary for central nervous system health and cognitive performance. One small randomized, placebo-controlled, double-blinded, repeated measures crossover study of 28 older adults (mean age 75 years) using dried rosemary leaf powder found that the smallest tested dose of 750 mg had statistically significantly better Cognitive Research Computerized Assessment System outcomes in speed of memory than the placebo (p=0.01). Note that in this study, the highest dose of 6 g had a significant impairing effect on the test (p<0.01). There were several limitations to the study, and more research is needed on the use of rosemary for any of these medical improvements.3

Another study of 68 young adults found that taking 500 mg rosemary leaf powder twice daily for one month improved prospective and retrospective memory performance by 14% when compared with a placebo group.7

• Other benefits: The German Commission, a scientific advisory board, has approved the use of rosemary leaf at 4 to 6 g (0.1 to 1 mL in essential oil form) per day for dyspepsia, high blood pressure, and rheumatism.1 Taking 500 mg rosemary leaf powder twice per day for one month significantly reduced anxiety and depression and improved sleep in a small study.7

Dosing and Safety
Rosemary supplements can be delivered in powder, tincture, capsule, or essential oil forms. They’re sometimes standardized to either polyphenolic content or gallic acid equivalents. A variety of doses have been used when assessing rosemary’s use in treating health conditions, thus making it difficult to develop universal dosing recommendations.8

Rosemary has Generally Recognized as Safe status in the United States when used orally in amounts typically found in foods.3,8 When used in therapeutic doses, as much as 6 g of powdered leaves has been used safely at a given time. Digestion of undiluted rosemary essential oil can cause adverse effects. Rosemary isn’t safe in therapeutic amounts during pregnancy due to its potential to induce uterine-stimulating effects. There isn’t enough evidence to fully evaluate its safety for lactating women.8

Potential adverse effects at high doses include coma or seizures, kidney damage, uterine bleeding, gastroenteritis, and vomiting. Rosemary supplementation also can cause moderate interactions with blood-thinning medications such as warfarin, Lovenox, aspirin, and NSAIDs. Because it can inhibit platelet aggregation, use caution when combining rosemary at a therapeutic dose with other supplements with similar effects.8

Culinary Tips
Rosemary is a staple in herbal blends such as poultry seasoning and Herbes de Provence. Poultry seasoning typically contains rosemary, sage, thyme, marjoram, nutmeg, and black pepper, while Herbes de Provence includes rosemary, thyme, basil, marjoram, lavender, savory, parsley, oregano, tarragon, bay leaf powder, and fennel.

Rosemary can be used fresh or dried to enhance the flavor of meat, poultry, and seafood as well as a variety of vegetables in recipes. It’s also used as a food preservative, approved by the European Union as safe and effective for this purpose.1

Potential culinary uses are endless. Consider infusing rosemary sprigs in olive oil, blending into butter to spread on rolls, sprinkling on popcorn, baking into desserts such as cake, or freezing into popsicles. Use a rosemary sprig as a beautiful and flavorful garnish in your next cocktail or mocktail.

Abbie Gellman, MS, RDN, CDN, Chef, owner of Culinary Nutrition Cuisine, suggests chopping rosemary and mixing it into cornbread. She also chops it into marinades for meat and poultry or adds it to onions and garlic sautéed for the start of a frittata.

Valeria Rech Mallett, RD, CDE, of Valeria Mallett Nutrition, suggests adding rosemary sprigs to plain water because it’s an inexpensive way to enhance flavor, boost water intake, and potentially reduce indigestion.

Recommendations for Clients
Many clients and nutrition programs are seeking natural ways to add flavor to recipes without adding sodium; rosemary, as well as other herbs in this family, is one way to intensify the flavor of dishes and complement other herbs and spices. Dietitians can help create menus for clients and facilities that include fresh or dried rosemary. A common herb, it can be found in most grocery stores, at farmers’ markets, and in commercial catalogs.

RDs should discuss therapeutic uses of rosemary with their patients, communicating that evidence is limited but assessing for potential drug and nutrient interactions and educating them on safe usage should they wish to take supplemental rosemary.

— Ginger Hultin, MS, RDN, CSO, is a nutrition and health writer based in Seattle. She’s a past chair of the Vegetarian Nutrition Dietetic Practice Group, a past president of the Chicago Academy of Nutrition and Dietetics, and owner of concierge nutrition practice, Champagne Nutrition LLC.

References
1. Andrade JM, Faustino C, Garcia C, Ladeiras D, Reis CP, Rijo P. Rosmarinus officinalis L.: an update review of its phytochemistry and biological activity. Future Sci OA. 2018;4(4):FSO283.

2. Kontogianni VG, Tomic G, Nikolic I, et al. Phytochemical profile of Rosmarinus officinalis and Salvia officinalis extracts and correlation to their antioxidant and anti-proliferative activity. Food Chem. 2013;136(1):120-129.

3. Pengelly A, Snow J, Mills SY, Scholey A, Wesnes K, Butler LR. Short-term study on the effects of rosemary on cognitive function in an elderly population. J Med Food. 2012;15(1):10-17.

4. US Department of Agriculture, Agricultural Research Service. FoodData Central. https://fdc.nal.usda.gov/

5. Stockinger K, Bissinger R, Bouguerra G, Abbès S, Lang F. Enhanced eryptosis following exposure to carnosic acid. Cell Physiol Biochem. 2015;37(5):1779-1791.

6. Valdés A, García-Cañas V, Artemenko KA, Simó C, Bergquist J, Cifuentes A. Nano-liquid chromatography-orbitrap MS-based quantitative proteomics reveals differences between the mechanisms of action of carnosic acid and carnosol in colon cancer cells. Mol Cell Proteomics. 2017;16(1):8-22.

7. Nematolahi P, Mehrabani M, Karami-Mohajeri S, Dabaghzadeh F. Effects of Rosmarinus offinalis L. on memory performance, anxiety, depression, and sleep quality in university students: a randomized clinical trial. Complement Ther Clin Pract. 2018;30:24-28.

8. Rosemary. Natural Medicines Database website. https://naturalmedicines.therapeuticresearch.com/databases/food,-herbs-supplements/professional.aspx?productid=154. Updated February 5, 2019. Accessed August 4, 2019.