Antibiotics kill the bacteria that are causing illness by bursting bacteria cell walls, and destroying the proteins and DNA that keep the bacteria alive. Unfortunately, they also kill the good bacteria in your gut that you need for healthy digestion, and interfere with your body’s ability to absorb some critical nutrients. Antibiotics and nutrient interactions are rarely discussed or listed as side effects on the drug label, but numerous hospital websites — most notably Mount Sinai — have made this information readily available.
“Nutrients are essential to the metabolic activities of every cell in the body. They’re used up in the process and need to be replaced by new nutrients in food or supplements. Some drugs deplete nutrients by speeding up this metabolic rate. These drugs include antibiotics (including penicillin and gentamicin),” writes Hyla Cass, M.D.
While there are hundreds of different antibiotics, most can be grouped into six classes that treat different conditions:
Since each of these medications is used to kill different bacteria in different parts of the body, each interacts differently with nutrients in your diet and supplements.
Several antibiotics and nutrient interactions are potentially detrimental both to your nutritional status and the efficacy of the medication. Antibiotics can interfere with your ability to absorb critical vitamins and minerals, which can lead to additional health problems in nutrient deficiency.
Antibiotics Deplete Friendly Gut Bacteria
Antibiotics kill bacteria. Their mission is to destroy the harmful ones that are causing acne or an ear infection, but they can also kill good bacteria that keep your digestive system healthy, including lactobacillus acidophilus and bifidobacterium bifidum.
Here’s how the Genetics Learning Center at the University of Utah describes what happens: “Friendly bacteria help keep you healthy in many ways, so when antibiotics kill friendly bacteria, your health can suffer because you lose these benefits. Additionally, losing friendly bacteria can give other types of bacteria room to multiply, leading to opportunistic infection. Sometimes opportunistic infection happens when bacteria from the environment get into your body and overrun friendly bacteria damaged by an antibiotic. Other times opportunistic infection begins when antibiotics disturb the balance of your resident microbes, and normally friendly bacteria multiply too quickly and become harmful.”
The authors continue to explain that short-term use of antibiotics often has fast recovery times while long-term use increases health risks by “upsetting the balance of resident microbes.”
All antibiotics can have this effect, regardless of the class. Probiotic foods and supplements can help to replenish these bacteria.
Antibiotics and Essential Mineral Interaction: Calcium, Magnesium, Iron, and Zinc
These minerals are critical for numerous processes in the body and must be acquired through diet. Because of the relative scarcity of these nutrients in our food (that’s a topic for another article), they are common supplements. Doctors advise that when taking antibiotics, it’s important to consider proper timing of mineral supplementation.
Per Dr. Cass, “Certain medications reduce the absorption of specific nutrients in the gastrointestinal tract by binding to them before they’re absorbed into the bloodstream. The antibiotic, tetracycline, for example, can block absorption by binding with minerals, such as calcium, magnesium, iron and zinc in the GI tract.”
This binding also effects the absorption of the antibiotic. According to a researcher, “Tetracycline should be taken one hour before or two hours after meals, and not taken with milk because it binds calcium and iron, forming insoluble chelates, and influencing its bioavailability… Results showed that even a little quantity of milk containing extremely small amounts of calcium severely impair the absorption of the drug, so that the presence of this metal ion should be carefully controlled in order to avoid decreasing the available tetracycline.”
Antibiotics can deplete iron, magnesium, calcium, and potassium by several potential mechanisms including the aforementioned chelation as well as enzyme activity. Effective supplementing to avoid antibiotic-induced nutritional deficiencies while maximizing the efficacy of the medication may come down to planning.
Iron may reduce the absorption of the antibiotics penicillamine, tetracyclines, and quinolones, if taken concurrently.
Magnesium can interfere with absorption of tetracyclines, quinolones, and nitrofurantoin, so Mount Sinai recommends supplementing one hour before or two hours after taking these medications.
Calcium can decrease absorption of tetracyclines and quinolones, so Mount Sinai recommends taking supplements 2–4 hours before or after taking the antibiotic.
Zinc can interfere with quinolones and tetracyclines as well, though apparently not doxycycline.
The University of Michigan Medical School recommends similarly that, if supplementing, to take magnesium, iron, zinc, or calcium an hour before or after taking the tetracycline.
Antibiotics May Interfere with Vitamin C Effects
According to information published on numerous hospital websites, including Mount Sinai, taking Vitamin C with tetracycline may increase levels of the antibiotic, but that the antibiotic may decrease the effects of Vitamin C in the body.
Antibiotics Deplete B Vitamins
Tetracylcine can interfere with B vitamin activity, and the B vitamins can interfere with tetracycline absorption. Mount Sinai states that B complex supplements and tetracycline should be taken at different times of day. Using these antibiotics in the long-term can lower the body’s levels of B2, B9 (folic acid), B7 (biotin), B6, and B12. The University of Michigan Medical School recommends that people taking tetracycline for longer than two weeks ask their doctors about supplementation.
Neomycin interferes with B-12 and folic acid activity by decreasing absorption or increasing elimination. University of Michigan Medical School recommends supplementing if taking neomycin for more than a few days.
Antibiotics Interfere with Vitamin K Absorption
According to Mount Sinai, antibiotics — particularly those in the cephalosporin family — reduce Vitamin K absorption. Use for more than ten days may also lower Vitamin K levels as these antibiotics kill the bacteria that makes Vitamin K.
Antibiotics + Supplementation
Each type of antibiotic functions differently in the body as it targets different bacteria. That’s why medical institutions recommend speaking to your doctor about potential antibiotic and nutrient interaction before you start supplementing. Ask your doctor about Lypo-Spheric® B Complex Plus that includes all the B vitamins that can be depleted by antibiotics, delivered in a way that enhances absorption for even people who have difficulty absorbing certain B vitamins. Lypo-Spheric® Vitamin C also uses a superior nutrient delivery system that means more Vitamin C is available in the body. Lypo-Spheric® Magnesium L-Threonate provides 18% of the RDA of magnesium using a salt of the mineral that is the only compound proven to raise magnesium levels in the brain.