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What you don't know about vitamins and herbs...

What you don't know about vitamins and herbs...

Approximately 52% of older adults take dietary supplements with their prescribed medications.

Americans spend as much as $35 billion annually on dietary supplements, with minimal to no evidence supporting their use.

Although vitamins and herbs may seem harmless, they can be dangerous for older adults when combined with certain medications.

This post will review common vitamins and herbs, potential benefits, indications for use, and interaction with standard medications.


Vitamins are essential, and our body depends on them to function. The best way to nourish our bodies with vitamins is through the things that we eat. Most vitamins are safe; however, vitamins can interact with certain medicines. Sometimes, high levels of specific vitamins can cause unpleasant side effects. Continue reading to learn about the benefits, interactions, and side effects of some common vitamins.


Iron is an essential mineral that our body uses to make a proteins that carry oxygen from the lungs to the body. Meat, beans, certain nuts, and green leafy vegetables such as spinach and kale contain iron.

Sometimes patients have medical conditions and are advised to take an iron supplement. However, people should only take iron supplements under the direction of a medical professional. Too much iron can cause constipation, nausea, vomiting, heartburn, black or dark-colored stools, temporary staining of the teeth, headaches, and unusual or unpleasant taste in the mouth.

Iron supplements may also cause some medicines to be less effective. Some of these medicines include certain antibiotics, medication taken for low thyroid, Parkinson's disease, and seizures.

Vitamin E and Omega 3s

Vitamin E helps to support hair, eyes, cholesterol level, and some essential chemicals (hormones) made by the body. Foods such as sunflower seeds, peanuts, spinach contain vitamin E. Omega-3's support heart and brain health. Fatty fish such as salmon, sardines, walnuts, and plant oils contain Omega-3 fatty acids. These vitamins have blood-thinning properties; too much of them can cause bruising and bleeding.

Vitamin E and Omega-3s supplements can increase bleeding risk when taken with warfarin (Coumadin), clopidogrel (Plavix), and non-steroidal anti-inflammatory medications like aspirin and ibuprofen.

Vitamin B Complex

Vitamin B's are well known to help with energy. They also aid in digestion (the process by which our body breaks down food), forming blood cells, supporting memory, bone, vision, mood, heart, hair, and skin health. Older adults are at risk for vitamin B12 deficiency, leading to memory problems, neuropathy (pins and needle feeling in feet and hands), weakness, fatigue, dizziness, and vision changes. Meat, plant-based milk, cheese, eggs, fortified nutritional yeast, and certain mushrooms contain vitamin B12.

Other vitamin B's that are important for body function include: B-1 (thiamine), B-2 (riboflavin), B-3 (niacin), B-5 (pantothenic acid), B-6 (pyridoxine), B-7 (biotin), B-9 (folic acid). Most vitamin B's have similar functions.

When it comes to vitamin B12, health care professionals worry about low levels. Some medications can decrease the body's ability to take up vitamin B12, including, Metformin, Colchicine (Colcrys), certain antibiotics, seizure medicines, heartburn medicines. Some medications can interfere with vitamin B12 levels, possibly causing false results.

Side effects of too much vitamin B can include feeling nervous, restless, and irritated.

Medicine interactions with other vitamin Bs can include the following:


Zinc is a vitamin found in various foods, including whole grains, milk products, baked beans, chickpeas, oysters, red meat, nuts such as cashews and almonds. Zinc has benefits to support a person's immune system, a unique network to protect against infection. It also fights free radicals, which are chemicals that can cause our body harm when found at high levels. Diabetes, heart disease, and cancer have been linked to free radicals. Our body needs no more than 8-11mg of this vitamin per day; higher doses taken through supplements can lead to unpleasant side effects, including nausea, cramps, diarrhea. It is essential to discuss the need for a zinc supplement with a licensed medical professional due to medication interactions.

Zinc supplements can interact with certain antibiotics, making them less effective. Some of the common antibiotics that zinc interacts with include: Ciprofloxacin (Cipro), Levofloxacin (Levaquin), Tetracyclines. Zinc can also reduce the effectiveness of NSAIDs.

Some medications can decrease zinc levels in the body, and people taking those medications may need a zinc supplement. Water pills such as thiazide diuretics, including hydrochlorothiazide and chlorthalidone, can decrease zinc levels in the body. Blood pressure medications such as Lisinopril (Zestril), Benazepril (Lotensin), and other medicines in this class called ACE inhibitors can decrease zinc levels.

Magnesium citrate

Magnesium Citrate is a vitamin that can help regulate blood pressure, supports some vital body functions, and increases energy. Spinach, swiss chards, bananas, and almonds are a great source of magnesium citrate. If you are eating a well-balanced diet, taking additional supplements can cause stomach upset or diarrhea. Very high doses can cause low levels of essential minerals in the body that help our body function. Low levels of some minerals can cause confusion, loss of energy, irritation, muscle weakness, nausea, vomiting.

Before starting a magnesium citrate supplement, it is essential to speak to your health care professional. Magnesium interacts with Digoxin (Lanoxin), a heart medicine. Low levels of magnesium can increase the levels of Digoxin in the body, which can be harmful. Taking magnesium at the same time as Digoxin can decrease how well the medication works in the body. Magnesium interacts with certain antibiotics such as Ciprofloxacin, Doxycycline, and Levofloxacin, reducing their effects. Magnesium can interact with many medicines, including those taken for osteoporosis.

Vitamin D

Vitamin D is an essential vitamin for bone health, immune, and brain health. The Food and Drug Administration recommends adults 65 and older to take 800 units of D3 daily. Older adults are generally at risk of having too little vitamin D. the primary source of vitamin D is the sun. It can also be found in, Fatty fish such as salmon, sardines, herring, mackerel, red meat, liver, egg yolks, breakfast cereals, regular milk, almond, coconut, soy, and cashew milk. Sometimes taking too many vitamin D supplements can cause kidney stones, stomach upset, poor appetite, constipation, and diarrhea. Very high levels can even cause kidney failure.

Vitamin D can interact with a few medications. Taking Vitamin D with Digoxin can increase the effects of the drug leading to an irregular heartbeat. Vitamin D can decrease the impact of another heart medicine called Diltiazem (Cardizem). High doses of vitamin D can interact with certain blood pressure medications such as hydrochlorothiazide (HCTZ) and other similar drugs, leading to kidney problems.


Calcium is an essential vitamin that helps support bone, teeth, and heart health. The recommendation is to take about 1000-1200 mg daily, including the diet amount. For example, a cup of yogurt has about 300mg of calcium. Too much calcium can be dangerous for the heart, cause stomach upset, constipation, and kidney stones.

Calcium can interact with certain antibiotics like tetracyclines making them less effective. It interacts with Alendronate (Fosamax), an osteoporosis medicine making it less effective; it generally should be taken about 2 hours before or after the medication. Calcium can also increase the levels of Digoxin in the body, making it harmful. Other interactions include some blood pressure medicines, cholesterol-lowering medicines, water pills, and seizure medicines. It is essential to take calcium supplements under the direction of a health care professional.

Herbal Supplements

It is crucial to treat herbal supplements like medicine; they have side effects and can interact with other medications. Your health care provider should know if you are taking any herbal supplements. Below I will discuss some of the more common herbal supplements, side effects, and medicine interactions.


Chamomile is known for its calming benefits. Patients taking this herb may experience allergic reactions such as stomach cramps, tongue thickness, itching, or hives. Chamomile can interact with Aspirin, Coumadin increasing the risk of bleeding. Chamomile can cause low blood pressure when taken with propranolol (Inderal). Chamomile can cause sleepiness, confusion, and falls when taken with certain depression medicines such as amitriptyline.


Echinacea is a herb known for its infection-fighting properties. The most common side effect is an unpleasant taste. It can increase the levels of some medications, including Itraconazole (Sporanox), Fexofenadine (Allegra), Lovastatin (Mevacor). Can be toxic to the liver when taken with Isoniazid, Ketoconazole, or Methotrexate.

St. John's Wort

St. John's John's Wort is an herb taken to treat depressed mood, anxiety, and sleep issues. Side effects can include sun sensitivity, headaches, dizziness, and sweating. Most people who are sensitive to ragweed also have a sensitivity to St. John's Wort. St. John's Wort can interact with some antibiotics, including sulfa-containing antibiotics and tetracyclines. St. John's Wort can also interact with some medications taken for depression, such as Fluoxetine (Prozac), Paroxetine (Paxil), Sertraline (Zoloft), etc.

Ginkgo Biloba

Ginkgo Biloba has been famous for its brain-boosting properties, often taken by older adults to prevent or treat dementia. Side effects of Ginkgo Biloba can include stomach upset and headache. Ginkgo Biloba should not be taken when taking Coumadin, Aspirin, or other NSAIDs due to increased bleeding risk. Ginkgo Biloba can also increase the risk of seizures when taken with Phenytoin (Dilantin) or Carbamazepine (Tegretol).


Ginseng is known for its energy-boosting properties and can help decrease blood sugar in patients with diabetes. Side effects of Ginseng can include increased blood pressure, headache, vomiting, insomnia, and tremors. Ginseng can interact with Digoxin lab levels causing false abnormal values.

Saw Palmetto

Saw Palmetto is generally taken for enlarged prostate, although there is no evidence that it works. Side effects of this herb can include stomach upset and decreased libido (sex drive). There is no known medication interaction but, avoid saw Palmetto with estrogen therapy.


Turmeric is well known to improve immune function and reduce inflammation, which means it helps with pain and swelling. Turmeric is also known to help with the way our body breaks down food and uses it for fuel. There are generally no side effects until doses reach more than 400mg per day. These may include low blood sugars in diabetic patients, diarrhea, headache, nausea, decreased iron levels in the body, and increased risk of kidney stones. Patients who have certain breast cancers, ovarian cancers, uterine cancers, or fibroids should not take Turmeric supplements because it can act like estrogen. Additionally, there is an increased risk of bleeding when taking Turmeric supplements with blood thinners.


I hope you found this post to be helpful, and please discuss any changes to your medicines, which include vitamins and herbs, with your health care provider. Depending on your medical history, specific vitamins and or herbs may not be safe for you to take.

Golden Oak Medicine PLLC is located in Asheville, NC. We provide primary care services for adults aged 55 years and older.

What you don't know about vitamins and herbs...

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