Even though herbal supplements may be from plant or herb sources, the active ingredients can still be potent chemicals. Because of this, herbal supplements can have drug interactions, even with each other or with food or alcohol. Unfortunately, these products are not labeled with safety warnings, and it is difficult for a consumer to know if an interaction may occur.
Herbal interactions with prescription medications or other chemicals can:
- interfere with how the drug may be broken down in the body
- enhance side effects of prescription medications
- block the intended therapeutic effect of a drug
In order to predict or prevent drug interactions, you need to be proactive in checking for possible drug interactions yourself in addition to asking your health care provider to screen for interactions.
The use of herbal supplements has a long history dating back thousands of years. Examples of important medicines extracted from botanicals include reserpine (a drug commonly prescribed for high blood pressure), morphine, penicillin, and vinca alkaloid anti-cancer drugs.
Today, herbal supplements and nutraceuticals can be purchased over-the-counter (OTC) and may be labeled “all-natural”. But that does not mean they are always safe. A nutraceutical product is a food or fortified food product that not only supplements the diet but also assists in treating or preventing disease, so provides medical benefits.
Nutraceuticals are not tested and regulated to the extent of pharmaceutical drugs.
Herbal supplements are sold in many different forms – dried leaves for teas, powdered, as capsules or tablets, or in solution.
Tell your doctor or pharmacist about all the medications you take, including:
- prescription drugs
- herbal supplements.
Be sure a drug interaction screen is conducted by a healthcare provider each time you start or stop a medication. Consult your doctor about any symptoms you are experiencing and discuss all herbal products prior to use.
Green tea is a popular drink that originated in China and has been promoted for stomach disorders, to lower cholesterol, as an anti-cancer antioxidant, as a stimulant, and to lessen belly fat, among other uses. In the U.S., it has gained popularity due to claims it can boost metabolism and aid in weight loss. Dried green tea leaves contain vitamin K, which can increase blood clotting. Large amounts of vitamin K may interfere with the activity of some blood thinners.
A substantial decrease in the INR (a measure of blood clotting) has been reported in patients treated with warfarin after consuming large quantities (1/2 to 1 gallon daily) of green tea. Patients treated with warfarin should probably avoid large amounts of green tea as it can interfere with the blood-thinning capabilities of warfarin, anisindione, and dicoumarol.
Moderate to high levels of vitamin K are also found in other foods such as asparagus, avocados, dill pickles, green peas, green tea, canola oil, margarine, mayonnaise, olive oil, and soybean oil. However, even foods that do not contain much vitamin K may occasionally affect the action of anisindione. There have been reports of patients who experienced bleeding complications and increased INR or bleeding times after consuming large quantities of cranberry juice, mangos, grapefruit, grapefruit juice, grapefruit seed extract, or pomegranate juice. Again, you do not need to avoid these foods completely, but it may be preferable to limit their consumption, or at least maintain the same level of use while you are on blood thinners.
Foods rich in vitamin K include beef liver, broccoli, Brussels sprouts, cabbage, collard greens, endive, kale, lettuce, mustard greens, parsley, soy beans, spinach, Swiss chard, turnip greens, watercress, and other green leafy vegetables. Moderate to high levels of vitamin K are also found in other foods such as asparagus, avocados, dill pickles, green peas, green tea, canola oil, margarine, mayonnaise, olive oil, and soybean oil.
Ginger is a commonly used spice and herbal supplement. Ginger has been used in the treatment and prevention of motion sickness, vertigo, to increase appetite, and to reduce stomach acidity. Ginger has also been used by some women under medical supervision to reduce severe nausea and vomiting in pregnancy.
Drug interactions with ginger are not well documented. However, it is known to inhibit thromboxane synthetase, a vasoconstrictor and agent in increases blood clotting. Ginger might prolong bleeding time and may cause interactions with anticoagulants like warfarin, aspirin, or other blood thinners. Pay attention to your ginger consumption if you are on Xarelto, Coumadin, aspirin or low-dose aspirin.
Black cohosh is a shrub-like plant found in North America. Black cohosh is often used for menopausal disorders (“hot flashes”), painful menstruation, uterine spasms, and vaginitis. However, prescription drugs broken down by certain liver enzymes may accumulate in the body and lead to toxicity if used with black cohosh. There is concern that black cohosh might also be toxic to the liver and may enhance liver toxicity with certain medications, such as:
- atorvastatin (Lipitor)
- acetaminophen (Tylenol)
Cranberry extract, powdered cranberries, and the fruit cranberries may exert an increased effect on blood thinners (anticoagulants) like warfarin and lead to bruising or bleeding. If you take an oral blood thinner, check with your doctor before consuming more than an occasional serving of cranberry or cranberry juice. You may need to have your International Normalized Ratio (INR) or other blood clotting lab test checked more frequently.
Brussels sprouts are named after the veggie’s history of cultivation in Belgium. Part of the cruciferous vegetable family, the sprouts’ cousins include cauliflower, kale, broccoli, cabbage, collard greens, and bok choy.
Low in calories, at less than 40 per cup, Brussels sprouts are also low-carb, with just 8 grams per cup raw, including 3 grams as fiber. And, they’re nutrient powerhouses, providing a range of vitamins, minerals, antioxidants, including plant protein.
Here are some of the major nutrients in a half cup of cooked Brussels sprouts:
- Calories: 28
- Protein: 2 grams
- Carbs: 6 grams
- Fiber: 2 grams
- Vitamin K: 137% of the RDI
- Vitamin C: 81% of the RDI
- Vitamin A: 12% of the RDI
- Folate: 12% of the RDI
- Manganese: 9% of the RDI
Brussels sprouts are antioxidant powerhouses. One study found that when volunteers ate about two cups of Brussels sprouts per day, damage at the cell level was slashed by 28%.
The fiber in Brussels sprouts (about 4 grams per cooked cup) helps regulate blood sugar levels, supports digestive health, and helps feed the beneficial gut bacteria tied to positive mood, immunity, and anti-inflammation. Just a half cup of cooked Brussels sprouts contains 2 grams of fiber, fulfilling up to 8% of your daily fiber needs
One cup of cooked Brussels sprouts provides over 81% of the RDI of vitamin C. This important nutrient acts as an antioxidant, supports immunity, vision, and iron absorption, and is needed for collagen production.
One cup of cooked Brussels sprouts packs over 137% of the recommended daily requirement for vitamin K. In addition to helping to clot blood, this nutrient plays a role in bone health and may help protect against bone loss. Vitamin K is essential for coagulation, the formation of blood clots that stop bleeding. Vitamin K may also play a role in bone growth and could help protect against osteoporosis, a condition characterized by progressive bone loss. In fact, one review of seven studies concluded that taking vitamin K supplements could increase bone strength and decrease the risk of bone fracture in postmenopausal women.
The anti-inflammatory power of Brussels sprouts is tied to a reduced risk of chronic diseases, including heart disease and cancer. Their anti-inflammatory compounds, which protect cells from DNA damage, also fend off aging and may help manage inflammatory conditions, including type 2 diabetes, rheumatoid arthritis, inflammatory bowel disease, and obesity. In one study, women who consumed more cruciferous veggies had lower levels of certain marketers of inflammation in their blood and urine.
Compounds in Brussels sprouts act like natural detoxifiers, meaning they help deactivate potentially damaging chemicals or shuttle them out of the body more quickly. A study showed that eating Brussels sprouts increased the levels of some detoxification enzymes by 15–30%.
In addition, the sulfur compounds in Brussels sprouts are known to reduce ulcer risk by limiting Helicobacter pylori (H. pylori) overgrowth and preventing bacteria from clinging to the stomach wall.
For vegan (or anyone who doesn’t eat fish or seafood), eating enough omega-3 fatty acids can be a challenge. Plant foods only contain alpha-linolenic acid (ALA), a type of omega-3 fatty acid that’s used less effectively in your body than the omega-3 fats from fish and seafood. This is because your body can only convert ALA to the more active forms of omega-3 fatty acids in limited quantities. Brussels sprouts are one of the best plant sources of omega-3 fatty acids, with 135 mg of ALA in each half-cup serving of cooked Brussels sprouts. Studies show that omega-3 fatty acids reduce blood triglycerides, slow cognitive decline, reduce insulin resistance and decrease inflammation.
Several studies have linked an increased intake of cruciferous vegetables to a decreased risk of diabetes. This is likely due to their antioxidant power and fiber content. The fiber helps to regulate blood sugar and insulin levels. Brussels sprouts also contain an antioxidant called alpha-lipoic acid that’s been studied for its potential ability to help improve insulin function. Insulin is a hormone that’s responsible for transporting sugar from your blood to your cells to keep your blood sugar levels under control. In one study, 12 patients with diabetes who were given alpha-lipoic acid supplements experienced increased insulin sensitivity. The researchers extrapolated that this was because the alpha-lipoic acid allowed insulin to work more efficiently to lower blood sugar.
How to Buy
Whether you buy them still attached to a long stalk or loose at the farmers’ market or grocery store, look for sprouts that are a tight bulb and have no yellowing. Consider how you’ll prepare them when it comes to what size you pick. Smaller ones are more difficult to cut.
How to Store
Store the sprouts in the fridge, and know that they’re pretty durable. Some suggest trimming, cleaning, drying, and finally storing them in the crisper, but most suggest waiting to clean and trim the sprouts until you’re ready to use them. I do either depending on how quickly I am going to use them.
How to Cook
One of the most delicious ways to enjoy Brussels sprouts is oven roasted. Simply slice in half or quarter, lightly toss in extra virgin olive (EVOO) or avocado oil, sea salt, and black pepper, and cook 30 to 40 minutes at 400 degrees until the outer leaves are golden and slightly crisp.
They can also be shaved and added to garden salads or skewered whole and grilled. Use EVOO sautéed shaved Brussels sprouts as a bed for lentils. Or add them to stir-fries and soups.
You can also steam Brussels sprouts, but be careful not to over cook them.
Quinoa Bowl with Crispy Brussels Sprouts, Eggplant and Tahini
Melissa Clark Image:Linda Xiao for The New York Times. Food Stylist: Monica Pierini.
For the Grain Bowl:
For the Grain Bowl:
- Heat oven to 425 degrees.
- Make the tahini dressing: Whisk together lemon juice, garlic and salt in a medium bowl. Let sit for 1 minute, then slowly whisk in oil, a few drops at a time, until emulsified. Whisk in tahini and enough water (by the teaspoon) to make a thin pourable sauce; taste and add more salt and lemon juice if needed. Set aside.
- Prepare the grain bowl: Place the brussels sprouts on a rimmed baking sheet, and the eggplant on another. Toss all vegetables with just enough olive oil and salt to coat. Roast brussels sprouts for 17 to 22 minutes and eggplant for 20 to 30 minutes, until vegetables are browned and tender. Toss vegetables once or twice while roasting.
- While vegetables are in the oven, make the quinoa: In a medium saucepan, place quinoa, 2 cups water and 1/4 teaspoon salt. Bring to a boil, and then lower to a simmer for 15 minutes, until the grains soften and water is absorbed. Transfer to a medium bowl and set aside.
- In a small bowl, whisk together lemon juice, maple syrup, remaining 1/4 teaspoon salt and the red-pepper flakes. As soon as the eggplant is done, toss immediately with the lemon red-pepper mixture to coat. Taste and adjust seasoning, if necessary.
- To serve, place quinoa in four bowls. Divide brussels sprouts, eggplant and tomatoes among the bowls, mounding the vegetables next to one another on top of the quinoa. Generously drizzle tahini dressing over the bowls and garnish with mint and more red-pepper flakes.