Wondering how much calcium you need per day?

Wondering how much calcium you need per day?  If your intake of calcium-rich foods might be low, or your doctor has suggested a calcium supplement here is some Registered Dietitian advice on how to choose a calcium supplement.

Why is calcium important?

Calcium is the most abundant mineral in the body. It is key for building and maintaining strong bones and teeth as well as supporting nerve function and muscle contraction. Calcium is also a mineral that is involved in blood pressure and blood clotting. Getting enough calcium is important for preventing osteoporosis, high blood pressure, colon cancer and may even help with premenstrual syndrome.

How much calcium do I need each day?

The Dietary Reference Intakes for calcium are shown below. The Recommended Dietary Allowance (RDA) is the total amount of calcium suggested from food AND supplements each day. The Tolerable Upper Intake Level (UL) is the amount you should not exceed per day between food and supplements to prevent negative effects such as kidney stones.

*Adequate Intake rather than Recommended Dietary Allowance.

How much calcium is in food?

You can get enough calcium from foods each day assuming that you enjoy foods such as milk, fortified plant-based beverages (such as soy milk, rice milk, or almond milk), yogurt and cheese. Other foods such as broccoli, kale, spinach, sardines, salmon (with bones) also supply calcium.

For a list of calcium in foods check out:  Food Sources of Calcium. 

Are you wondering how dairy milk and plant-based milk compare? Check out this article I did here: Milk, soy beverage, almond beverage or rice beverage – which is better?

Who might be low in calcium?

Many children over the age of 4 and up and teenagers fail to consume enough calcium each day.  The same is true for many adult men.  Adult women are even more likely to be low in their intake of calcium.

In our practice, the most common clients that are low in calcium may include those with a lactose-intolerance or dairy allergy, those that dislike dairy foods, vegetarians, those that have been following a restrictive diet and those with an eating disorder.  The good news is, with a little planning you can achieve sufficient calcium either from food alone or from food and calcium supplements combined.

What type of calcium supplement is best?

The two main types of supplements are calcium carbonate and calcium citrate. Calcium carbonate has the advantage that it is often cheaper and you have to swallow fewer pills in general to get the same amount of elemental calcium. Take calcium carbonate with meals since it requires extra stomach acid for absorption.

If you have decreased stomach acid or are taking acid-blocking medication, consider taking calcium citrate since it is more readily absorbed in your intestine and can be taken with or without food. Another advantage of calcium citrate is that it may cause less gas, bloating and constipation than calcium carbonate.

Coral calcium, which is made from marine coral beds, has been marketed as superior but in fact, it is chemically similar to calcium carbonate. Those that have a seafood allergy should avoid it.

If you are not keen on swallowing pills you can also consider a liquid or chewable calcium supplement.

Regardless of which calcium supplement you choose, be sure to look at the label carefully to assess the dose in each calcium pill. Look on the side of the package or container to find out how much elemental calcium is in each supplement versus the total weight of the entire tablet which is often displayed on the front.

What factors influence calcium absorption?

1. Vitamin D

Take calcium supplements alongside a vitamin D supplement since it increases calcium absorption significantly.

2. Dose at one time

Take a maximum of 500-600 mg of calcium at any one time to maximize absorption.

3. Iron

Avoid taking calcium supplements at the same time as iron supplements since they compete for absorption.

4. Sodium

Be mindful of your sodium intake since high sodium diets increase calcium losses in the urine.

5. Caffeine

Coffee and tea have a moderate impact on calcium loss in the urine although 1 cup of coffee results in a loss of only 2-3 mg of calcium so the loss is considered insignificant.

6. Phytic acid & oxalic acid

Phytic acid naturally found in foods such as whole grains, beans, and nuts as well as oxalic acid found in foods such as spinach, sweet potatoes, rhubarb and beans can reduce calcium absorption. Note however though that the amount of calcium recommended in the Dietary Reference Intake table above does accommodate for this.  If you are consuming a varied diet there is little reason to worry.

7. Some medications

Some medications can decrease calcium absorption so it is best to speak to your doctor and pharmacist for further advice.

8. Alcohol

Limit alcohol to no more than 2-3 drinks per day since too much alcohol negatively influences calcium and vitamin D absorption.