How Much Magnesium Does a Woman Need?

The average adult woman needs about 310 to 320 milligrams of magnesium a day.
Image Credit: Anna Pustynnikova/iStock/GettyImages

Many women will hear at some point about their risk of iron deficiency because of their menstrual cycle or their need for calcium because of the risk of osteoporosis in later years. But magnesium's benefits are just as important, especially for women as they head into their senior years.



The average adult woman needs about 310 to 320 milligrams of magnesium a day.

What Is Magnesium?

Magnesium is a dietary mineral that's important for a wide range of functions. The body needs magnesium for 300 chemical reactions in the body, and without it, you would not be able to contract your muscles or keep your heart beating. Magnesium also plays a role in the way your nerves send and receive signals, and it helps with your blood pressure and blood sugar levels. It is even important in making protein, bone and DNA.


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According to the National Institutes of Health, most American diets fall short in providing the amount of magnesium people need. The Academy of Nutrition and Dietetics notes that magnesium is what's known as a major mineral, which is needed in higher amounts than trace minerals, such as zinc or iron. Some people — such as those with conditions like celiac disease or Type 2 diabetes — could have trouble absorbing magnesium from their diet.

Magnesium deficiencies can also be caused by ongoing low intakes and chronic alcoholism.

People's magnesium needs depend on their age and sex. In the case of the average adult women, the National Institutes of Health recommends 310 to 320 milligrams, but pregnant or lactating people need a little bit more. Pregnant people should get 350 to 360 milligrams and breastfeeding people should get 310 to 320 milligrams.

Good dietary sources of magnesium include legumes, nuts and seeds, whole grains, leafy vegetables, dairy products and fortified breakfast cereals. According to the Cleveland Clinic, the best sources of magnesium you can find are pumpkin seed kernels (168 milligrams per 1 ounce), almonds (80 milligrams per 1 ounce), boiled spinach (78 milligrams per half-cup) and cashews (74 milligrams per 1 ounce).


Supplementing Magnesium in Your Diet

Most people won't see the symptoms of low magnesium intake unless they are severely deficient. This is because the kidneys can help the body retain it by limiting the amount excreted through urine. When a magnesium deficiency becomes severe, however, it can manifest itself in loss of appetite, nausea, vomiting, fatigue and weakness.

Read more: ‌How Does B12 Deficiency Cause Iron-Deficiency Anemia?


Women with low magnesium levels will want to supplement their diet. A substantial magnesium dosage for women over 50 could be beneficial particularly if they want to stay active.


A September 2014 study published in ‌American Journal of Clinical Nutrition‌, which noted that magnesium deficiency can cause poor physical performance, looked at 139 older women with an average age of 71.5 years as they attended a fitness program over the course of 12 weeks. One group of them took an oral magnesium supplement, and the other group took a placebo.


In this case, the magnesium dosage for women over 50 was 300 milligrams a day. The study found that the women who took this supplement had better performance of physical activity, specifically short physical performance, chair stand times and 4-meter walking speeds. The conclusion was that magnesium supplements could be used to prevent age-related loss of peak physical performance.

Magnesium can be found in both multivitamin-mineral supplements as well as in mineral-only supplements. If you're looking for the best magnesium supplements, talk to your doctor about a brand he or she would recommend. The best magnesium supplements will likely contain magnesium in the form of magnesium asparate, magnesium citrate, magnesium lactate and magnesium chloride.


Even the best magnesium supplements will vary in their strength and the amount per dosage, and the amount you need can be determined by your doctor depending on how severe your deficiency is.

Be sure to limit your supplementation to 350 milligrams, as this is the upper limit for adults. Too high a dosage of magnesium can result in diarrhea, nausea and abdominal cramping and — in extreme cases — irregular heartbeat or cardiac arrest.


What Are Magnesium Benefits

Still, when taken in healthy amounts, the benefits are all there. Supplementary magnesium benefits can include lowered blood pressure, reduced insulin resistance and increased bone density.

The Kansas University Medical Center even lists such magnesium benefits as decreased symptoms of PMS and reduced migraine symptoms, and it adds that magnesium could be good for such ailments as depression, anxiety, muscle cramps, constipation, kidney stones, osteoporosis, insomnia, fibromyalgia and asthma.


But Harvard Health encourages you to be wary of any supplements marketing magnesium benefits that sound too good to be true, like curing muscle tension or low energy. These supplements might be touted as "super pills," but there isn't any evidence to support their claims.

Read more: ‌How to Determine if a Vitamin or Supplement Is Actually Right for You

Other Tips for Magnesium

When you're taking magnesium in supplement form, there are a few other important recommendations you should keep in mind. The Mayo Clinic encourages taking magnesium supplements with meals, as taking them on an empty stomach might cause you to have diarrhea.

If you're taking magnesium in tablet form, and you don't want to swallow it whole, you might be able to crush it up and sprinkle it on in your food; however, this is not a viable choice from some tablets, so you should seek your doctor's guidance before going this route.

If you are taking regular doses at the direction of your doctor and you miss one, take it as soon as possible unless you are closely approaching the time for your next dose. In that case, simply resolve to forgo the dose you missed and take your next dose at its regular time to avoid having too much at one time. Missing a dose occasionally will not deplete the stores you are building up.

With this knowledge, you'll be well on your way to having sufficient magnesium levels — and all the health benefits that come along with them!




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