What if I told you that those medicinal herbs you toss into your dish at the last minute for a burst of flavor might actually be antioxidative, anti-inflammatory, antibacterial secret weapons that can lower your cholesterol and glucose, improve your cognition and mood, and even guard against cancer?
Today, we’ll be asking and answering the questions: what are medicinal herbs or culinary medicinal herbs? Who and what are they for? And what does the science say about them? Read on to learn more.
What is a medicinal herb?
First off, we’ll answer the easy question: what is a medicinal herb? Don’t confuse them for medicinal spices, which we’ll be covering in an upcoming blog. The easiest way to tell the difference: for chefs like me, herbs are leaves, while spices are everything else (flower buds, flowers, stems, root, bark, seeds, rhizomes).
So for today, we’ll just be focusing on herbs, aka “the leafy part”—but if you think that narrow focus means we won’t have a lot to talk about, you’d be wrong! There are a huge variety of herbs out there, and you might be surprised to learn just how many of them have incredible medicinal properties that have been thoroughly researched.
Types of medicinal herbs
Let’s get straight to the good part: what does the science say about which herbs are good for what symptoms and conditions? Here are ten of my favorites, Looks like Simon and Garfunkel had the right idea when they sang about parsley, sage, rosemary and thyme…
If getting a whiff of a fragrant rosemary shrub calms you down, you’re not alone: research shows that the smell of rosemary actually triggers free radical scavenging activity in your body and decreases the level of the stress hormone cortisol in your body. (By the way, you can find more tidbits like that in my ChefMD’s Big Book of Culinary Medicine.) But that’s not all rosemary can do. Rosemary has strong antioxidant properties, due to the high levels of carnosic acid and carnosol found in the leaf. A 2018 Reviews on Recent Clinical Trials report found that rosemary suppressed the activation of inflammatory cytokines and shut down specific enzymes involved in inflammation during in vitro experiments.
Another major benefit of rosemary comes in the realm of cognition and mental health; in 2003, a randomized study of 140 subjects, using a cognitive assessment battery test and self-assessment mood scale, found that inhalation of rosemary and lavender oils enhanced cognitive function. Rosemary has long been thought to help with memory—in fact, Greek students over 2000 years ago placed sprigs of it in their hair during exams!—so it’s fascinating to finally see science back up these age-old remedies.
Rosemary oil or extract has also been found to reduce stress and depression, improve vascular health, help control blood glucose levels, reduce toxic chemical-induced liver damage and cirrhosis, and even have an anticarcinogenic effect by reducing the expression of a number of proinflammatory genes. A recent randomized controlled clinical trial found it to be equivalent to minoxidil at creating hair regrowth, but with less itching. And meat marinades made with rosemary drop cancer causing chemical deposits on hamburgers by 79%.
Thyme is a delicious, earthy herb you’ll find in various cuisines, particularly Mediterranean ones as the plant thrives in a hot climate. But did you know that thyme also has considerable antimicrobial, antioxidant, antibacterial, anti-inflammatory, antispasmodic, and antifungal effects—and might even be an effective anti-cancer weapon?
A 2010 study from the International Journal of Food Microbiology found that thymol—the active ingredient in thyme—can reduce bacterial resistance to common drugs, including penicillin, increasing the antibiotic susceptibility of drug-resistant bacteria. And a fascinating 2012 study looked at the effect of wild thyme on human breast cancer cells and found that the extract was “a promising candidate in the development of novel therapeutic drugs for breast cancer treatment,” while a study from the same year focusing on colon cancer found similar results indicating that thyme extract “may have a protective effect against colon cancers.”
According to a controlled trial from 2018, thyme honey mouth rinse has efficacy against mucositis caused by radiation, and a thyme honey nasal spray against chronic rhinosinusitis resulted in fewer bloody noses and adhesions than a placebo spray.
Peppermint & spearmint
There’s nothing like a mug full of fresh mint tea. Mint is well-known for some of its medicinal purposes, like mitigating nausea, but did you know studies have found that it’s also antimicrobial, antiviral, antioxidant, antitumor, and even antiallergenic?
Peppermint and stomach aches go hand in hand, as anyone who’s ever had a cup of mint tea to settle their stomach will know. One double blind placebo-controlled randomized trial from 2006 looked at how peppermint affected its participants with irritable bowel syndrome; it found that 75% of the patients in the peppermint oil group showed a greater than 50% reduction of symptoms score, compared to just 38% in the placebo group.
Spearmint, a close cousin of peppermint, has its own set of benefits. A randomized controlled study from 2016 found that spearmint extract improved working memory in both men and women with age-associated memory impairment. Folks who received 900 mg/day of spearmint extract saw a 15% increase in the quality of working memory and spatial working memory accuracy, compared to the placebo group. The peppermint group also reported improvement in their ability to fall asleep, their vigor-activity, their total mood disturbance, and their alertness and behavior following wakefulness, relative to the placebo group.
Sweet-smelling lavender has long been used as a remedy for anxiety and sleeplessness—and with good reason, it turns out! A randomized, controlled study from 2018 looked at the effects of lavender oil aromatherapy on anxiety and sleep quality in patients undergoing chemotherapy, in which 70 patients were randomly assigned to a lavender oil group, a tea tree oil group, and a control group with no oil. Researchers compared trait anxiety values both before and after chemotherapy and found “a significant difference in the lavender group.” And a systematic review and meta-analysis from 2019 which aimed to assess the efficacy of lavender on anxiety and anxiety-related conditions found that “overall, oral administration of lavender essential oil proves to be effective in the treatment of anxiety.”
But that’s not all lavender is good for: a 2017 double-blind cross over clinical trial carried out on 100 menopausal women found that lavender aromatherapy decreased the menopause symptoms for those using it, compared to the control group. Other studies have found that it’s also antibacterial, antifungal, carminative (smooth muscle relaxing), sedative, antidepressive and even effective for burns and insect bites!
Everyone who’s ever been to an Italian restaurant knows about basil, but have you heard of Tulsi basil? Also known as “holy basil,” this planet indigenous to India has been used in Ayurvedic medicine for centuries and claims a whole slew of benefits such as being antiinflammatory, analgesic, antipyretic, antidiabetic, hepatoprotective, hypolipidemic, antistress, and immunomodulatory.
This 2017 systematic review of the existing clinical literature on tulsi basil found that the herb was found to have “therapeutic effects on metabolic disorders, cardiovascular disease, immunity, and neurocognition,” suggesting that “tulsi is an effective treatment for lifestyle-related chronic diseases including diabetes, metabolic syndrome, and psychological stress.” Widely used in Ayurvedic medicine, the leaf extract can also be a dietary supplement. A two month uncontrolled Indian trial found that the leaf of Tulsi basil was reported effective in those with generalized anxiety disorder.
Fresh-smelling lemongrass is a staple in many Asian cuisines—but flavor isn’t the only thing it’s bringing to the (dinner) table thanks to its antioxidant, anti inflammatory, and antimicrobial properties, among others.
A 2017 study which evaluated the anti-inflammatory activity of lemongrass essential oil in pre-inflamed human dermal fibroblasts found that the lemongrass oil “significantly modulated global gene expression and robustly impacted signaling pathways, many of which are critical for inflammation and tissue remodeling processes.” The authors added that the study provided “the first evidence of the anti-inflammatory activity of [lemongrass essential oil] in human skin cells and indicates that it is a good therapeutic candidate for treating inflammatory conditions of the skin.”
And a 2019 study found that “lemongrass extract induced apoptosis in colon cancer cells in a time and dose-dependent manner without harming healthy cells in vitro”—which indicates that lemongrass has the “potential to be developed as a supplemental treatment for colorectal cancer.”
More clinical trials are needed in this area, but in one small open-label human clinical trial in 2010, in which the effects of lemongrass tea was observed on 31 patients with hypertension, researchers found that the lemongrass tea intake had a significant effect on reducing the patient’s blood pressure.
You might not recognize this one from your local grocer, but hyssop—part of the mint family—is a natural antioxidant that has been a staple in herbal medicine for ages, often for symptoms of gastrointestinal and respiratory tract infections as well as the common cold.
A 2017 study looking at plants in the Lamiaceae family, of which hyssop is a member, found a strong and direct antiviral effect “with prominent activity against enveloped viral species… Some in vivo experiments suggest that use of Lamiaceae representatives could help in prevention and treatment of some viral diseases. A possible reduction of side effects of diseases and conventional drug therapy are also some aspects worth further investigations.”
And a 2019 animal study looking at the effect of hyssop leaves on gastric ulcers and found that it had a “gastroprotective effect… comparable to that of standard drug ranitidine,” vindicating hysspo’s traditional role as a “carminative and antispasmodic” herb.
Borage—a herb also known as starflower, bee bush, bee bread, and bugloss—is rich in gamma linoleic acid (GLA), an omega-6 fatty acid that has been shown to decrease inflammation.
One 2013 animal and test tube study found that borage seed oil helped protect against oxidative cell damage which could contribute to inflammation, significantly increasing the lifespan of the fruit fly it was tested on.
A 18-month, randomized, and double-blind trial from 2014 which used borage seed oil to treat rheumatoid arthritis found that patients who received the oil showed “meaningful clinical responses after 9 months, improvements which persisted for 18 months, and a response similar to matched patients from an RA registry.” And a double‐blind, placebo‐controlled clinical trial from 2007, which looked at the effects of borage oil-coated undershirts on atopic dermatitis in 32 children, found that the group which wore borage oil undershirts for two weeks showed statistically significant improvements in their erythema and itch compared to the placebo group.
Turns out sage isn’t just good for amping up butternut squash—it’s also an antioxidant, antimicrobial, anti-inflammatory and anticancer powerhouse that’s great brain food!
A number of in vitro and animal studies have confirmed that several species of salvia (often used as ane umbrella term for 500+ types of sage) contain active compounds that may enhance cognitive activity and protect against neurodegenerative disease. And several types of salvia have even been shown to produce “antidepressant and anxiolytic-like effects via animal models of depression and anxiety.”
A fascinating review from 2017 aimed to look at all the up-to-date information on the pharmacological findings reported for sage, ultimately concluding that “on the basis of the available literature evidence, this plant shows anticancer, anti-inflammatory, antinociceptive, antioxidant, antimicrobial, hypoglycemic, hypolipidemic, and memory-enhancing effects. The effectiveness of S. officinalis as an antinociceptive, hypolipidemic, and memory-enhancing medicinal plant has been confirmed with clinical trials.”
Most human studies have used Salvia officinalis and Salvia lavandulaefolia in extract form, and sometimes for novel uses. One randomized double blind placebo controlled trial showed that eight weeks of supplementation of the former improved insulin resistance and body mass index in patients with polycystic ovarian syndrome. And both on its own and when combined with clotrimazole, sage extract effectively treats vulvovaginal candidiasis.
You might know this as the hardy leaf you have to remember to fish out of your sauces, soups and stews before serving them. But bay leaves—aka the “Laurus nobilis” leaf—is also an anti-inflammatory and antiviral herbal remedy that’s been used to treat immunological diseases for centuries.
A 2019 study which aimed to shed light on the anti-inflammatory mechanism of bay leaves looked at the effect of the extract on mouse bone marrow-derived macrophages. They found that the bay leaf extract “consistently suppressed NLRP3 inflammasome activation,” indicating that by doing so it was able to control inflammation.
And a 2013 study found that even molecular-size fractions of bay leaf inhibited colorectal cancer cell growth, suggesting that bay leaves “might be relevant to protecting against early events in sporadic colorectal cancer.”
It turns out that your favorite herbs aren’t just flavorful—they’re also healthful! Sounds like just another reason to take culinary medicine seriously and include more fresh herbs in your cooking. Time to get to work on that home garden of yours!
(Remember: Nature therapy is a far more diverse and interesting field than people might realize—it’s much more than just “going outside!”—and so the purpose of these blogs is to show you the exciting range, diversity, and nuance of the many therapeutic interventions that fall under the umbrella of nature therapy. You can check out the other blogs I’ve written on the site, on topics like gardening for dementia, therapeutic horticulture, pet therapy, adventure therapy, blue care, ecotherapy, care farms, forest bathing, hydrotherapy, breathwork in nature, earthing and grounding, greening the indoors, and light therapy.)
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