Rosemary vs Thyme - Health impact and Nutrition Comparison

Introduction

Thyme and rosemary are two significant members of the herb family. Herbs have been used not only as flavourings in foods, but also as medicinal remedies since ancient times. In this article, we will look into the nutritional comparison of thyme and rosemary and discuss how they affect our health, based on scientific evidence.

Classification

Both thyme and rosemary are part of the Laminacaea family, also known as the mint, sage or dead nettle family. They share this family with other culinary and medicinal herbs, such as oregano, basil, mentha, salvia and catnip.

Thyme belongs to the Thymus genus. More than 400 varieties of thyme are known, the most commonly used are Thymus vulgaris and Thymus serpyllum.

Rosemary or Salvia rosmarinus belongs to the Salvia genus. It is also scientifically known as Rosmarinus officialis.

Appearance

Thyme has rounded sharp leaves, growing in clusters. The leaves are brighter green in colour and get darker as they age.

The leaves of rosemary are dark green, resembling needles. They also grow in clusters along the branches.

Taste and Use

Rosemary and thyme are both used as a seasoning in various cuisines and as medicine against numerous maladies.

The taste of thyme is herbal, sharp and minty. Lemon thyme can also have a citrus-like flavour. When dried, thyme does not lose much of its taste.

The leaves of rosemary exude a clear and bright aroma. This herb is a part of the classic French spicy mixture of "Provence grass" and "bouquet garnish". Rosemary leaves are often described to have a lemon-pine flavour that pairs well with different meats.

History

These herbs were known in ancient Metirreanean cultures to signify various ideas.

Thyme was considered to be a symbol of courage in ancient Rome. Roman soldiers bathed in water infused with thyme, exchanged with each other and pinned springs of thyme on their armor before battle. Thyme was also used in ancient Egypt as part of embalming rituals.

The Latin name for rosemary translates as “dew of the sea”. In ancient Greece rosemary was known to signify remembrance, happiness and love. Rosemary springs were often used at funerals and weddings. Greek scholars even wore rosemary wreaths during examinations, as they believed the herb to help their memory. 

Nutrition

The nutritional values below are presented for raw, fresh thyme and rosemary leaves.

Macronutrients and Calories

Rosemary and thyme are both packed with nutrients. Thyme is only a little more dense in nutrients, containing 65% water, while rosemary consists of 68% water.

One average serving size of rosemary is two times larger than that of thyme. Thyme’s average serving size is half a teaspoon.

Calories

Small amounts of these herbs do not significantly alter the caloric value of the dish they are added to. However, between these two herbs, rosemary is higher in calories.

Protein and Fats

Thyme is richer in protein and rosemary contains a larger amount of fats. That being said, rosemary has a more favourable protein quality, while thyme has a more preferable fatty acid content. 

Being lower in protein, rosemary contains some level of all essential amino acids. Thyme lacks methionine, phenylalanine and histidine.

The predominant fat type in thyme is the polyunsaturated fat, while rosemary contains more saturated fatty acids.

Carbohydrates

Thyme is higher in carbohydrates, even though rosemary and thyme contain the same amount of fiber.

Vitamins

Thyme is richer in vitamins, containing overall two times more, when compared to rosemary. Thyme is particularly higher in vitamin C, vitamin A and vitamins B2 and B3.

Rosemary, on the other hand, contains a higher level of vitamin B5 and vitamin B9.

What about the coverage of our needs? Thyme covers 6 times more of our needs of vitamins, as it contains 7 times more of vitamin C and 3 times more of vitamin B2.

Minerals

Thyme is the winner in this category as well, containing twice the amount of minerals as rosemary. Thyme is significantly higher in most minerals, namely iron, magnesium, zinc, copper, phosphorus, calcium and manganese.

The two herbs have a similar potassium content with rosemary being only a little higher.

Glycemic Index

Due to a high level of dietary fiber and a relatively low level of sugars, the glycemic index of herbs, such as thyme and rosemary is very difficult to measure. However, one study has demonstrated consumption of thyme tea to result in a lower glycemic index when compared to rosemary tea (1).

Thyme and rosemary tea were also found to possess qualities inhibiting an enzyme that breaks down sugars in the gastrointestinal tract, called alpha glucosidase (1).

Thyme and rosemary are assumed to have low glycemic indices.

Weight Loss & Diets

As seasonings, rosemary and thyme do not alter the caloric value of the meal drastically. One average serving of rosemary used in a dish contains almost 1 calorie. Thyme has fewer calories and a smaller serving size. The caloric content found in an average serving for thyme is equal to 0.4.

Based on their nutritional content, thyme is preferable for low calories, low fat and low glycemic index diets, while rosemary is preferable for low carbs diet.

A study has found rosemary leaf extract to have the potential to limit weight gain induced by a high-fat diet in mice (2). This property may be due to a compound found amply in rosemary called carnosic acid (3).

Health Impact

Health Benefits

Thyme and rosemary have been used in traditional medicine as healing herbs for centuries. Here, we will look at the scientific evidence about the beneficial effects of these herbs on health.

Cardiovascular Health

Studies on animals have shown dietary supplementation of rosemary to attenuate adverse effects of cardiac remodeling caused by myocardial infarction (4).

Due to a high level of phenolic phytochemicals, rosemary has also been studied to have significant anti-inflammatory, antioxidant, anti-atherosclerotic, anti-thrombotic, as well as blood glucose, blood pressure and cholesterol lowering qualities (5).

Due to a compound found in high quantities in thyme, called thymol, this herb exhibits anti-inflammatory, antioxidant, antimicrobial and immunomodulatory activities (6).

Thyme may also protect against cardiac and hepatic damage induced by consumption of heated frying oil (7). 

Thyme and rosemary both have the potential to inhibit formation of blood clots without prolonging bleeding time (8).

Diabetes

Rosemary extract and the polyphenols found in it, such as rosmarinic acid and carnosic acid, have been researched to have insulin-like effects, exhibiting protective properties against hyperglycemia in animals with type 2 diabetes mellitus (9).

Thyme has also demonstrated antihyperglycemic effects, which may potentially be used for supplementary treatment of diabetes and diabetic complications (10). 

Cancer

Numerous studies have researched rosemary to have anticancer effects against colon, pancreas, breast, prostate, cervical, bladder, ovarian, lung cancers and leukemia, through various mechanisms (11).

Thyme has been studied less extensively. Nevertheless, thyme has demonstrated protective properties against breast, colon and liver cancers (12, 13).

Nervous System and Cognitive Abilities

Inhalation of rosemary oil can have a positive effect on brain wave activity, autonomic nervous system functions and overall mood (14). Rosemary aroma has also been studied to improve cognitive performance (15).

Animal studies have shown thyme to have the potential to relieve anxiety (16).

Downsides and Risks

Drug Interactions

Herbs, such as thyme and rosemary can bind to certain proteins, inhibit or induce enzymes, which can lead to an increased or decreased activity of certain drugs, when used simultaneously.

Some of the medication that can negatively or positively interact with thyme are (17):

• antithyroid drugs
• caffein
• fluorouracile
• hormonal drugs

Rosemary can interact with following medications (18):

• lithium
• diuretics
• anticoagulants
• ACE inhibitors

People on these medications have to be advised to use thyme and rosemary with caution.

Summary

To sum up, rosemary is higher in calories and fats, while thyme contains more protein and sugars. Thyme is also richer in most minerals and vitamins, particularly vitamin C, vitamin B2 and iron. Nevertheless, rosemary is significantly higher in folate.

While most herbs have beneficial effects on health, rosemary has been researched more extensively to have cardioprotective, antidiabetic and anticancer effects. Thyme and rosemary should be consumed carefully when used with certain medications.

Sources.

1. https://www.jstage.jst.go.jp/article/fstr/16/1/16_1_39/_pdf
2. https://pubmed.ncbi.nlm.nih.gov/19918713/
3. https://pubmed.ncbi.nlm.nih.gov/21676274/
4. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5426768/
5. https://pubmed.ncbi.nlm.nih.gov/27178264/
6. https://onlinelibrary.wiley.com/doi/abs/10.1002/ptr.6109
7. https://www.researchgate.net/publication/343047965
8. https://pubmed.ncbi.nlm.nih.gov/18378282/
9. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5622728/
10. https://www.researchgate.net/publication/338686150
11. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5133115/
12. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6479806/
13. https://www.ncbi.nlm.nih.gov/books/NBK92774/
14. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3700080/
15. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3736918/
16. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4936652/
17. https://core.ac.uk/download/pdf/143841098.pdf
18. https://www.researchgate.net/publication/221876211