It would be nice to get a short list of all the supplements you should take. Unfortunately, it is not that simple. Even though supplements are marketed as safe and natural alternatives to support health, they are not appropriate for everyone.
There is no universal list of supplements that every woman should be taking just because she has reached a certain age. Like prescription medications, supplements also come with side effects and drug interactions. Some can also cause additional problems in women with specific medical conditions.
As women enter their 40s various hormone changes including a decline in estrogen levels can affect bone health and overall nutritional needs. It is important to understand what our body needs before adding supplements. This will make sure the supplements you are taking are safe and beneficial.
In many cases, food should be the first source of nutrients. Whole foods provide nutrients like vitamins and minerals that can’t always be substituted by supplements. Whenever possible, it is important to consider what nutritional needs can be met through dietary changes before considering supplements.
When we assess nutritional needs, it is also important to recognize the difference between low intake and a nutrient deficiency. Not eating the daily requirement of a nutrient does not always mean a deficiency. A person may consume less than the recommended amount of a nutrient for a period of time and still maintain normal body stores.
On the other hand, someone may consume adequate amounts and still become deficient. That is where appropriate laboratory testing combined with medical history can help assess if additional supplementation is actually needed.
In this article we will look at 5 supplements worth considering for women over 40.
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1. Calcium
Calcium is the most common mineral in the body with about 98% stored in the bones. It helps maintain strong bones and teeth. It also supports muscles and nerves to function well. The recommended daily intake of calcium for women over 40 is 1000 mg per day. Calcium deficiency can increase the risk for osteoporosis. This causes bones to be weak and increases the risk of falling and bone fractures.
Who should consider supplementation
Women may be at an increased risk of calcium deficiency if they:
- Avoid dairy products or follow a restrictive diet
- Have medical conditions with absorption issues such as celiac disease
- Have low vitamin D levels which can affect calcium absorption
What the research shows
According to the NIH, supplements containing calcium and vitamin D can reduce the risk of osteoporosis. Supplements might be beneficial if dietary intake is not sufficient to meet the daily requirement.
Blood tests can be done to measure the total calcium level in the blood but it is not a good reflection of the calcium status in the body since most calcium is stored in the bones. An X-ray scan (DEXA scan) of the bone is generally recommended for women above 65 and some younger women with risk factors.
Risks
Excessive calcium intake can increase the risk of kidney stones.
Forms and how to take it
Calcium can interfere with the absorption of some medicines. Avoid taking calcium carbonate within four hours of taking levothyroxine, a thyroid medication, or any calcium supplement within two hours of taking quinolone antibiotics such as ciprofloxacin. There are two forms of calcium supplement: calcium carbonate and calcium citrate. Calcium carbonate is cheaper, but is best absorbed when taken with food.
Calcium citrate is just as well absorbed on a full as on an empty stomach. If you have low stomach acid, which is common as you get older, ask your doctor or pharmacist whether calcium citrate is a better choice for you. The upper limit from all sources for adults is 2,000 to 2,500 mg a day.
Remember that calcium in food doesn’t raise your risk of developing kidney stones, as it is calcium in supplements that can be a problem. The body does not absorb well a single large dose of calcium, so it’s better to divide a 1,000 mg daily dose into two smaller doses than to swallow one large tablet. The NIH says calcium is absorbed best at 500 mg or less at a time.
Takeaway
- Assess your daily calcium intake from dietary sources.
- Consider a calcium supplement if it is not possible to consistently meet the daily requirement through food alone.
- Review all medications and supplements with a pharmacist or healthcare provider for possible drug interactions before starting.
2. Magnesium
Magnesium is an abundant mineral involved in various processes in the body including energy production and normal nerve and muscle function. It is also involved in maintaining bone structure and health. 50-60% of magnesium in the body is present in the bones. The daily recommended dietary allowance for women is 320 mg. Low magnesium has been associated with migraines.
Who should consider supplementation
Women may be at an increased risk of magnesium deficiency if they:
- Have gastrointestinal diseases like Crohn’s disease or celiac disease
- Have Type 2 diabetes which can increase urinary magnesium loss due to higher concentrations of glucose in the kidney.
What the research shows
Research shows that magnesium supplementation marginally lowers blood pressure. People with higher intakes or increased levels of magnesium have lower risk of cardiovascular diseases like heart disease and stroke. Some studies show higher magnesium intake is associated with increased bone mineral density.
Risks
High doses of magnesium from dietary supplements can cause side effects like diarrhea, nausea, and abdominal cramping.
Forms and how to take it
Ask your pharmacist how long you should wait after taking certain medications before taking a magnesium supplement. Magnesium may interfere with the absorption of oral bisphosphonates (osteoporosis medications) and the tetracycline and quinolone antibiotics. Don’t forget to mention that you take certain medications when asking your pharmacist to recommend a magnesium supplement. Long-term use of proton pump inhibitors, as well as taking certain diuretics (water pills), can result in low levels of magnesium.
Know the signs of taking too much. Diarrhea, nausea, and cramping can result from taking too much magnesium. Very high doses taken from supplements, laxatives, or antacids may cause abnormally low blood pressure and heart rhythm problems.
The Tolerable Upper Intake Level (UL) for magnesium is 350 mg a day from supplements and medications only. There is no UL set for getting magnesium from food. Not all magnesium supplements are the same. Magnesium aspartate, citrate, lactate, and chloride are better absorbed by the body than magnesium oxide and sulfate.
Magnesium is also the active ingredient in some heartburn remedies and laxatives, which is a hint at what happens to any extra your body can’t absorb.
Takeaway
- Review your diet and medications to determine whether you are not getting enough magnesium
- Always take magnesium supplements as directed.
- Discuss with a pharmacist or healthcare provider before starting a supplement especially if you have other medical conditions.
3. Vitamin D
Vitamin D is a fat soluble vitamin present in foods. Our bodies can also produce vitamin D when ultraviolet (UV) rays from sunlight strike the skin and trigger its production. Vitamin D plays an important role in helping the body absorb calcium and maintain healthy bones and muscles. The daily recommended intake for most adults is 15 mcg (600 IU).
Who should consider supplementation
Women may be at an increased risk of vitamin D deficiency if they:
- Have limited sun exposure
- Have darker skin pigmentation which can reduce the skin’s ability to produce vitamin D from sunlight
- Have conditions that interfere with fat absorption, such as celiac disease or Crohn’s disease
What the research shows
Clinical trials have shown that vitamin D and calcium supplements may increase bone mineral density in some postmenopausal women. There is mixed evidence that supplementation reduces falls or fracture rates.
Risks
Vitamin D is generally safe when taken at recommended doses.
Excessive supplementation can lead to increased calcium levels which can cause complications including kidney stones.
Forms and how to take it
Vitamin D supplements come in the form of vitamin D2 or vitamin D3. Although both forms raise blood levels of vitamin D, vitamin D3 raises blood levels higher and for a longer period of time, so vitamin D3 is the preferred form. The upper limit for vitamin D in adults is 100 mcg (4,000 IU) a day from all sources.
Although it’s virtually impossible to get too much vitamin D from the sun, vitamin D toxicity, a condition marked by nausea, weakness, confusion, kidney stones, and high blood calcium levels, is almost always the result of taking vitamin D supplements.
Be wary of supplement combinations, too: Taking vitamin D and calcium supplements together may increase your risk of side effects. Vitamin D is a fat-soluble vitamin, which means it’s better absorbed when you take it with a meal that contains some fat.
Still, some vitamin D is absorbed even if you take it on an empty stomach. Certain drugs can interfere with vitamin D’s actions, or vitamin D can decrease the effects of certain drugs. For example, the weight-loss drug orlistat decreases vitamin D absorption; steroids such as prednisone can decrease vitamin D levels; high-dose vitamin D supplements may interfere with some statins; and taking vitamin D supplements while you’re taking thiazide diuretics can lead to abnormally high blood calcium levels.
Takeaway
- Review your diet, sun exposure, and medical history to determine if you are at risk for Vitamin D deficiency.
- Take Vitamin D supplements as directed.
- Discuss with a pharmacist or healthcare provider whether a supplement is appropriate for you, especially if you have risk factors or other medical conditions.
4. Vitamin B12
Vitamin B12 is a water soluble vitamin naturally found in animal-based foods. It helps maintain healthy nerve cells as well as supports DNA synthesis. It is also required for the formation of red blood cells. The recommended daily intake for adults is 2.4 mcg daily.
Who should consider supplementation
Women may be at increased risk of Vitamin B12 deficiency if they:
- Have pernicious anemia
- Have gastrointestinal disorders such as Crohn’s disease or celiac disease
- Have undergone gastric bypass surgery or other procedures that affect nutrient absorption
- Take metformin for diabetes
- Take acid-reducing medications such as proton pump inhibitors (omeprazole, pantoprazole) or H2 blockers (famotidine) for extended periods.
What the research shows
Vitamin B12 supplements can be used to treat and prevent deficiency in people with low vitamin B12 levels. Some observational studies have shown that higher concentrations of vitamin B12 are associated with an increased risk of certain cancers. Current evidence does not show that vitamin B12 supplements cause cancer.
Risks
Vitamin B12 is generally considered safe even at higher doses.
Forms and how to take it
People who produce little stomach acid, including older adults and people who take acid-reducing medications, may not absorb enough vitamin B12 from food. Vitamin B12 in foods is bound to protein, and your body needs stomach acid to free B12 from the protein so it can be absorbed.
But the B12 in supplements isn’t bound to protein, so your body doesn’t need stomach acid to absorb it, though it still needs intrinsic factor. Metformin and acid-reducing medications such as omeprazole (Prilosec), lansoprazole (Prevacid), and cimetidine can lower your vitamin B12 levels. If you take these medications, talk with your doctor or pharmacist about whether you should have your vitamin B12 level checked.
There are different kinds of vitamin B12. Cyanocobalamin is the most common form in supplements, and methylcobalamin is the other one you will see. Your body can use both. Some marketers claim that methylcobalamin is a more “active” form than cyanocobalamin, but the NIH does not recommend one form over another.
There is no upper limit for vitamin B12. Large doses of vitamin B12 (for example, 500 to 1,000 mcg) may seem excessive, given that the daily requirement is only 2.4 mcg. But your body absorbs only a small percentage of the vitamin B12 you take when you consume these large doses.
So far, researchers have not found any harmful effects from taking large amounts of vitamin B12. Certain people need extra vitamin B12.
People with pernicious anemia, a condition in which the body does not make intrinsic factor, a protein needed to absorb vitamin B12, typically need vitamin B12 shots (injections). Very high doses taken by mouth can also be effective. As for dose, a vitamin B12 supplement by itself will provide the highest amount of vitamin B12. Multivitamin and B-complex supplements usually have much less.
Takeaway
Women with gastrointestinal disorders, restrictive diets or on long term metformin or acid reducing medications should discuss vitamin B12 testing with their healthcare provider.
5. Iron
Iron is a mineral that plays a significant role in the body. It is a component of hemoglobin, the protein in red blood cells that transports oxygen from the lungs to the body. Without enough iron, the body cannot produce enough healthy red blood cells.
This can result in iron deficiency anemia. The daily recommended intake for women ages 19-50 is 18 mg. A hemoglobin level can be used to screen patients for low iron while a serum ferritin level is commonly used to assess the body’s iron stores. Women with iron deficiency anemia may experience gastrointestinal disturbances, weakness, fatigue, and difficulty concentrating.
Who should consider supplementation
- Women with heavy menstrual bleeding or those who frequently donate blood.
- Women with gastrointestinal disorders like celiac disease, ulcerative colitis or Crohn’s disease
- Women who have undergone certain gastrointestinal surgical procedures that result in dietary restrictions or abnormal iron absorption
What the research shows
Iron supplementation is used to treat iron deficiency and iron-deficiency anemia. Treatment can restore iron and hemoglobin levels. Ferritin and hemoglobin testing can help identify those most likely to benefit from treatment.
Risks
Unnecessary supplementation may increase the risk of adverse effects. Excess iron can cause side effects including constipation and upset stomach. Excess buildup can lead to iron overload which can damage organs.
Iron can also interact with certain medications and reduce the absorption of some antibiotics and thyroid medications.
Forms and how to take it
Most iron supplements are one of four forms: ferrous sulfate, ferrous gluconate, ferric citrate, or ferric sulfate. Different forms of iron have different amounts of elemental (usable) iron, which is the number to look for on the Supplement Facts label when comparing different iron supplements. The upper limit for adults is 45 mg a day unless a clinician prescribes more.
High doses, especially on an empty stomach, cause stomach upset, nausea, constipation, and abdominal pain. Extremely high doses can cause significant harm. Calcium and proton pump inhibitors such as omeprazole, which lowers stomach acid, reduce iron absorption, and iron in turn interferes with levothyroxine and levodopa, so take these at different times of the day.
Vitamin C (found in abundance in orange juice, peppers, and tomatoes) can increase iron absorption. People with hereditary hemochromatosis should not take vitamin C or iron supplements. Ask your doctor if iron should be taken every day or every other day.
Traditionally, iron supplements were taken once or twice daily. However, in a Swiss trial in 18- to 40-year-old women who were iron depleted (but not anemic), taking 60 mg of iron on alternating days resulted in better iron absorption (22 percent) than taking 60 mg of iron every day (16 percent).
That’s because the hormone hepcidin, which blocks the body’s absorption of iron, goes up after a daily dose, meaning less of the next dose will be absorbed. If daily iron upsets your stomach, ask your doctor if it might be OK for you to try taking iron on alternate days instead.
Bottom Line
Consider discussing iron testing with your healthcare provider before starting an iron supplement. For most women, supplementation should be guided by symptoms and laboratory results rather than taken routinely.
The Five at a Glance
The interactions a pharmacist checks first
There are only five nutrients, but they all interact with at least one common prescription in one of three ways: the drug slowly drains the nutrient over months; the drug reduces absorption of the nutrient; or the nutrient binds to the drug and interferes with absorption. If you fall into any of these categories, don’t give up on the supplement. Talk to your pharmacist first.
| Medication | Supplement | What happens | What to do |
|---|---|---|---|
| Levothyroxine | Calcium carbonate, iron | The thyroid dose absorbs poorly within 4 hours of calcium carbonate; iron interferes too | Take levothyroxine first; calcium carbonate at least 4 hours later; separate iron as well |
| Quinolone antibiotics (ciprofloxacin, moxifloxacin) | Calcium, magnesium | The antibiotic absorbs poorly within 2 hours of calcium; magnesium interferes too | Separate the doses; ask the pharmacist for the gap |
| Tetracycline antibiotics | Magnesium | The antibiotic absorbs poorly when the doses are close together | Separate the doses |
| Oral bisphosphonates (osteoporosis) | Magnesium | The drug absorbs poorly when the doses are close together | Separate the doses |
| Proton pump inhibitors (omeprazole, lansoprazole) and H2 blockers | Vitamin B12, iron, magnesium | Less stomach acid cuts the B12 and iron absorbed from food; long-term PPI use lowers magnesium | Test rather than stop the drug |
| Metformin | Vitamin B12 | Lowers B12 levels over time | Ask for a B12 level |
| Thiazide diuretics | Vitamin D | Vitamin D supplements can push blood calcium too high | Check with the pharmacist before adding vitamin D |
| Statins | Vitamin D | High-dose vitamin D may make the statin work less well | Keep vitamin D at standard doses unless prescribed |
| Steroids (prednisone) | Vitamin D | Lowers vitamin D levels | Consider testing |
| Orlistat | Vitamin D | Reduces vitamin D absorption | Ask about a supplement and timing |
| Dolutegravir | Calcium | Drug levels drop when the two are taken together | Take it 2 hours before or 6 hours after calcium |
| Levodopa | Iron | Iron interferes with absorption | Separate the doses |
How to Decide Without Guessing
Laboratory testing is not necessary before taking every supplement, but it is worth considering for some supplements. This is especially important if you have symptoms or risk factors that would increase your chance for deficiency.
- Iron testing is recommended especially if you experience heavy menstrual bleeding or persistent fatigue as these can be signs of anemia. Ask your healthcare provider about a ferritin level to help assess your iron stores and if supplementation is necessary.
- Vitamin B12 testing may be beneficial if you are on metformin, have restrictive diet or long-term acid reducing medications. These factors can lower vitamin B12 levels over time. Obtaining a B12 level can help identify deficiency and help guide you if supplementation is needed.
- Routine vitamin D level is not recommended for most healthy adults. Vitamin D testing can be considered if you have limited sun exposure or other risk factors for deficiency.
- Routine magnesium and calcium testing is usually unnecessary for most women as blood levels do not always accurately reflect total body stores. Focus on evaluating dietary intake first and ensuring that calcium- and magnesium-rich foods are regularly included in your diet.
Supplements can be beneficial when used appropriately to help meet nutritional needs. However, they should never be a replacement for a balanced diet. The decision to take a supplement should be considered based on individual health status and dietary intake along with other factors including prescription medications and medical conditions.
When possible it is best to focus on meeting nutritional needs through food first. For women over 40, calcium, magnesium, vitamin D, vitamin B12, and iron supplementation may be worth considering while using laboratory testing when appropriate to guide supplementation decisions.
When in doubt, pharmacists are among the most accessible healthcare professionals who can help guide your decision. They can help assess if it is safe and beneficial for you to take a supplement based on your specific circumstances.
Selam Melka, PharmD, is a pharmacist with more than ten years of experience in clinical pharmacy and acute care.
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