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By Kerri-Ann Jennings
Many people take calcium supplements hoping to strengthen their bones.
However, they may have drawbacks and even health risks, including raising the risk of heart disease (1).
Many people take calcium supplements hoping to strengthen their bones.Shutterstock
This article explains what you need to know about calcium supplements, including who should take them, their health benefits and potential risks.
Why Do You Need Calcium?
In the bloodstream, it's used to send nerve signals, release hormones like insulin and regulate how muscles and blood vessels contract and dilate (2).
It's so important that if you don't get the recommended amount in your diet, your body will take it from your skeleton and teeth to use elsewhere, weakening your bones.
So how much calcium do you need each day?
Below are the current recommendations from the Institute of Medicine, by age (2):
- Women 50 and younger: 1,000 mg per day
- Men 70 and younger: 1,000 mg per day
- Women over 50: 1,200 mg per day
- Men over 70: 1,200 mg per day
There are also recommended upper limits for calcium intake. The cap is 2,500 mg per day for adults up to age 50 and 2,000 mg per day for adults over 50 (2).
It's possible to get sufficient amounts through your diet. Foods that contain it include dairy products, certain leafy greens, nuts, beans and tofu.
However, people who don't eat enough calcium-rich foods might consider taking supplements.
Bottom Line: Your body uses calcium to build strong bones, send nerve signals and contract muscles. While it's possible to get enough of it in your diet, some people might need to consider supplements.
Who Should Take Calcium Supplements?
When your calcium intake is insufficient, your body will remove calcium from your bones, making them weak and brittle. This can result in osteoporosis.
Since women are at a higher risk of osteoporosis, many doctors recommend that they take calcium supplements, especially after reaching menopause.
Because of this, older women are much more likely to take calcium supplements (2).
If you don't get the recommended amount through your diet, supplements can help fill the gap.
You might also consider calcium supplements if you:
- Follow a vegan diet.
- Have a high-protein or high-sodium diet, which may cause your body to excrete more calcium.
- Have a health condition that limits your body's ability to absorb calcium, such as Crohn's disease or inflammatory bowel disease.
- Are being treated with corticosteroids over a long period of time.
- Have osteoporosis.
Bottom Line: Calcium supplements may benefit those who are not getting enough calcium from food and women who have reached menopause.
The Benefits of Calcium Supplements
Calcium supplements may have several health benefits.
They May Help Prevent Bone Loss in Postmenopausal Women
After menopause, women lose bone mass due to a decline in estrogen.
Luckily, supplements may help. Several studies have suggested that giving postmenopausal women calcium supplements—usually around 1,000 mg per day—may reduce bone loss by 1–2 percent (3).
The effect seems to be greatest in women with low calcium intakes and during the first two years of taking supplements.
Plus, there doesn't seem to be any additional benefit to taking larger doses (4).
They May Help With Fat Loss
Studies have associated low calcium intake with a high body mass index and high body fat percentage (5).
A 2016 study examined the effects of giving a daily 600-mg calcium supplement to overweight and obese college students with very low calcium intakes.
The study found that those given a supplement containing 600 mg of calcium and 125 IUs of vitamin D lost more body fat on a calorie-restricted diet than those who did not receive the supplement (6).
It's often recommended to take vitamin D with calcium, since it helps calcium function.
Calcium May Help Lower the Risk of Colon Cancer
According to one large study, calcium from dairy products and supplements may lower the risk of colon cancer (7).
An earlier review of 10 studies found similar results (8).
Supplements May Help Improve Metabolic Markers
Several studies have suggested that taking calcium supplements might improve metabolic markers, especially when taken with vitamin D.
In a 2016 study, 42 pregnant women took supplements containing calcium and vitamin D. Several of their metabolic markers improved, including blood pressure and markers of inflammation (9).
Other research has shown that the children of women who took calcium supplements while pregnant have lower blood pressure at age seven than the children of mothers who did not take them (10).
In a recent study, more than 100 overweight, vitamin D-deficient women with polycystic ovary syndrome were given either a calcium and vitamin D supplement or placebo pill.
However, other studies have shown no improvements in the metabolic profiles of dieters who took supplements containing both calcium and vitamin D (6).
Bottom Line: Studies have linked taking calcium supplements with a lower risk of colon cancer and blood pressure, as well as fat loss and increases in bone density.
Possible Dangers of Calcium Supplements
Recent research suggests that calcium supplements may, in fact, cause some health problems. However, the evidence is mixed.
They May Increase Risk of Heart Disease
Perhaps the most controversial suggestion about calcium supplements is that they may increase the risk of some types of heart disease, including heart attack and stroke.
More conclusive research is needed to determine the effect of calcium supplements on heart health.
High Levels Have Been Linked to Prostate Cancer
High levels of calcium have been linked to prostate cancer, although the research on this link is also conflicting.
However, a randomized controlled study that gave 672 men either a calcium supplement or placebo every day for four years showed that participants did not have an increased risk of prostate cancer.
In fact, participants who took the supplement had fewer cases of prostate cancer (21).
Other research has suggested that dairy products may be the culprit. A review of 32 articles reported that consuming dairy products—but not calcium supplements—was linked to an increased risk of prostate cancer (26).
Risk of Kidney Stones May Increase
There is some evidence that calcium supplements increase the risk of kidney stones.
One study gave more than 36,000 postmenopausal women either a daily supplement containing 1,000 mg of calcium and 400 IU of vitamin D or a placebo pill.
The results showed that those who took the supplement had an increased risk of kidney stones (27).
Furthermore, while supplement users in the study experienced an overall increase in hip bone density, they didn't have a lower risk of hip fractures.
Consuming more than 2,000 mg of calcium a day from your diet or supplements is also linked to an increased risk of kidney stones, according to the Institute of Medicine (2).
Other sources say that the risk of kidney stones increases when calcium intake exceeds 1,200–1,500 mg per day (28).
High Levels of Calcium in Your Blood
Having too much calcium in your blood leads to a condition called hypercalcemia, which is characterized by many negative symptoms, including stomach pain, nausea, irritability and depression.
It can be caused by several things, including dehydration, thyroid conditions and taking high levels of calcium supplements.
Excessive vitamin D supplements may also lead to hypercalcemia by encouraging your body to absorb more calcium from your diet.
Bottom Line: Calcium supplements may increase the risk of heart disease and prostate cancer, although the link is unclear. Extremely high levels of calcium from any source may have negative health effects.
Things to Consider When Taking Calcium Supplements
If you take calcium supplements, there are several factors you should be aware of.
How Much Should You Take?
Calcium supplements can help fill the gap between how much calcium you get in your diet and how much you need per day.
Remember, the recommended amount for most adults is 1,000 mg per day and increases to 1,200 mg per day for women over 50 and men over 70.
Therefore, if you typically only get around 500 mg per day through food and need 1,000 mg per day, then you can take one 500-mg supplement daily (28).
However, choose your dose wisely. Taking in more calcium than you need can cause problems (29).
You May Need to Split up the Dose
It's important to check the amount of calcium in the supplement you choose.
Your body can't absorb large doses of it at once. Experts recommend taking no more than 500 mg at a time in supplement form (1).
Make sure to tell your doctor and pharmacist if you are taking calcium supplements, since they can interfere with how your body processes certain medications, including antibiotics and iron.
This way the calcium is less likely to inhibit the absorption of the zinc, iron and magnesium that you consume in your meal.
Dangers of Too Much Calcium
Remember, you only need 1,000–1,200 mg of calcium each day. There's no benefit to taking more than that. In fact, you could experience problems if you do.
Problems include constipation, hypercalcemia, calcium buildup in soft tissues and trouble absorbing iron and zinc (2).
Bottom Line: When you're taking calcium supplements, it's important to consider the type, amount and whether they may interact with other medications you take.
Different Types of Calcium Supplements
Calcium supplements come in different forms, including tablets, capsules, chews, liquids and powders.
One key difference between these types of supplements is the form of calcium they contain.
The two main forms are:
- Calcium carbonate
- Calcium citrate
These two forms differ in how much elemental calcium they contain and how well they're absorbed. Elemental calcium refers to the amount of calcium that is present in the compound.
This is the cheapest and most widely available form. It contains 40 percent elemental calcium and therefore usually delivers a lot of calcium in a small serving.
However, this form is more likely to cause side effects, such as gas, bloating and constipation. It is recommended that calcium carbonate be taken with food for optimal absorption (30).
This form is more expensive. Twenty-one percent of it is elemental calcium, meaning you may need to take more tablets to get the amount of calcium you need.
However, it's more easily absorbed than calcium carbonate and can be taken with or without food.
Calcium citrate is the form recommended for people with irritable bowel syndrome.
It's also the better choice for those with low levels of stomach acid, a condition common among older people and those taking medications for acid reflux (30).
Bottom Line: The two main forms of calcium supplements are calcium carbonate and calcium citrate. Calcium carbonate needs to be taken with food and is less effective if you have low levels of stomach acid.
Food Sources of Calcium
It's best to get nutrients from food rather than supplements.
Nevertheless, if you think you're not getting enough calcium in your diet, consider eating more of these foods:
- Dairy, including milk, cheese and yogurt
- Canned fish with bones, such as salmon or sardines
- Certain leafy greens including collard greens, spinach and kale
- Edamame and tofu
- Beans and lentils
- Fortified foods and drinks
Bottom Line: You can get all the calcium you need each day from food. Calcium-rich foods include yogurt, certain leafy greens, tofu and canned fish.
Take Home Message
Calcium supplements can help people who are at risk of osteoporosis, as well as those who don't get enough calcium in their diets.
While some research suggests a link between calcium supplements and heart disease, the link is not clear.
However, it is known that getting more than the recommended amount of calcium from any source may raise your risk of kidney stones.
Calcium supplements are probably fine in small doses, but the best way to get calcium is from food. Strive to incorporate a variety of calcium-rich foods in your diet, including non-dairy sources.
Reposted with permission from our media associate Authority Nutrition.
EcoWatch Daily Newsletter
By Tom Duszynski
The coronavirus is certainly scary, but despite the constant reporting on total cases and a climbing death toll, the reality is that the vast majority of people who come down with COVID-19 survive it. Just as the number of cases grows, so does another number: those who have recovered.
In mid-March, the number of patients in the U.S. who had officially recovered from the virus was close to zero. That number is now in the tens of thousands and is climbing every day. But recovering from COVID-19 is more complicated than simply feeling better. Recovery involves biology, epidemiology and a little bit of bureaucracy too.
How does your body fight off COVID-19?<p>Once a person is exposed the coronavirus, the body starts producing <a href="https://www.mblintl.com/products/what-are-antibodies-mbli/" target="_blank">proteins called antibodies to fight the infection</a>. As these <a href="https://www.statnews.com/2020/03/27/serological-tests-reveal-immune-coronavirus/" target="_blank">antibodies start to successfully contain the virus</a> and keep it from replicating in the body, symptoms usually begin to lessen and you start to feel better. Eventually, if all goes well, your immune system will completely destroy all of the virus in your system. A person who was infected with and survived a virus with no long-term health effects or disabilities has "recovered."</p><p>On average, a person who is infected with SARS-CoV-2 will feel ill for about seven days from the onset of symptoms. Even after symptoms disappear, there still may be small amounts of the virus in a patient's system, and they should stay <a href="https://www.cdc.gov/coronavirus/2019-ncov/if-you-are-sick/steps-when-sick.html" target="_blank">isolated for an additional three days</a> to ensure they have truly <a href="https://health.usnews.com/conditions/articles/coronavirus-recovery-what-to-know" target="_blank">recovered and are no longer infectious</a>.</p>
What about immunity?<p>In general, once you have recovered from a viral infection, your body will keep cells called lymphocytes in your system. These cells "remember" viruses they've previously seen and can react quickly to fight them off again. If you are exposed to a virus you have already had, your antibodies will likely stop the virus before it starts causing symptoms. <a href="https://dx.doi.org/10.5114%2Fceji.2018.77390" target="_blank">You become immune</a>. This is the <a href="https://www.ncbi.nlm.nih.gov/books/NBK27158/" target="_blank">principle behind many vaccines</a>.</p><p>Unfortunately, immunity isn't perfect. For many viruses, like mumps, immunity can wane over time, leaving you <a href="https://www.sciencedaily.com/releases/2016/04/160421145747.htm" target="_blank">susceptible to the virus in the future</a>. This is why you need to get revaccinated – those "booster shots" – occasionally: to prompt your immune system to make more antibodies and memory cells.</p><p>Since this coronavirus is so new, scientists still don't know whether people who recover from COVID-19 are <a href="https://www.cdc.gov/coronavirus/2019-ncov/hcp/faq.html" target="_blank">immune to future infections of the virus</a>. Doctors are finding antibodies in ill and recovered patients, and <a href="https://www.cdc.gov/coronavirus/2019-ncov/hcp/clinical-guidance-management-patients.html" target="_blank">that indicates the development of immunity</a>. But the question remains how long that immunity will last. Other coronaviruses like <a href="https://doi.org/10.1002/jmv.25685" target="_blank">SARS and MERS produce an immune response</a> that will protect a person at least for a short time. I would suspect the same is true of SARS-CoV-2, but the research simply hasn't been done yet to say so definitively.</p>
Why have so few people officially recovered in the US?<p>This is a dangerous virus, so the Centers for Disease Control and Prevention is being extremely careful when deciding what it means to recover from COVID-19. Both medical and testing criteria must be met before a person is <a href="https://www.cdc.gov/coronavirus/2019-ncov/hcp/disposition-in-home-patients.html" target="_blank">officially declared recovered</a>.</p><p>Medically, a person must be fever-free without fever-reducing medications for three consecutive days. They must show an improvement in their other symptoms, including reduced coughing and shortness of breath. And it must be at least seven full days <a href="https://health.usnews.com/conditions/articles/coronavirus-recovery-what-to-know" target="_blank">since the symptoms began</a>.</p><p>In addition to those requirements, the CDC guidelines say that a person must test negative for the coronavirus twice, with the <a href="https://www.cdc.gov/coronavirus/2019-ncov/if-you-are-sick/care-for-someone.html" target="_blank">tests taken at least 24 hours apart</a>.</p><p>Only then, if both the symptom and testing conditions are met, is a person officially considered recovered by the CDC.</p><p>This second testing requirement is likely why there were so few official recovered cases in the U.S. until late March. Initially, there was a <a href="https://www.nytimes.com/2020/03/18/health/coronavirus-test-shortages-face-masks-swabs.html" target="_blank">massive shortage of testing in the U.S.</a> So while many people were certainly recovering over the last few weeks, this could not be officially confirmed. As the country enters the height of the pandemic in the coming weeks, focus is still on <a href="https://www.cdc.gov/coronavirus/2019-nCoV/hcp/clinical-criteria.html" target="_blank">testing those who are infected</a>, not those who have likely recovered.</p><p>Many more people are being tested now that states and private companies have begun <a href="https://www.cdc.gov/coronavirus/2019-ncov/cases-updates/testing-in-us.html" target="_blank">producing and distributing tests</a>. As <a href="https://www.dispatch.com/news/20200406/coronavirus-in-ohio-from-its-rocky-start-testing-for-covid-19-slowly-ramping-up" target="_blank">the number of available tests increases</a> and the pandemic eventually slows in the country, more testing will be available for those who have appeared to recover. As people who have already recovered are tested, the appearance of any new infections will help researchers learn <a href="https://www.statnews.com/2020/03/24/we-need-smart-coronavirus-testing-not-just-more-testing/" target="_blank">how long immunity can be expected to last</a>.</p>
Once a person has recovered, what can they do?<p>Knowing whether or not people are immune to COVID-19 after they recover is going to determine what individuals, communities and society at large can do going forward. If scientists can show that recovered patients are immune to the coronavirus, then a person who has recovered could in theory <a href="https://www.vox.com/2020/3/30/21186822/immunity-to-covid-19-test-coronavirus-rt-pcr-antibody" target="_blank">help support the health care system</a> by caring for those who are infected.</p><p>Once communities pass the peak of the epidemic, the number of new infections will decline, while the number of <a href="https://www.newsweek.com/china-says-passed-peak-coronavirus-epidemic-covid-19-1491863" target="_blank">recovered people will increase</a>. As these trends continue, the risk of transmission will fall. Once the risk of transmission has fallen enough, community-level isolation and social distancing orders will begin to relax and businesses will start to reopen. Based on what other countries have gone through, it will be <a href="https://www.nature.com/articles/d41586-020-00154-w" target="_blank">months until the risk of transmission is low</a> in the U.S.</p><p>But before any of this can happen, the U.S. and the world need to make it through the peak of this pandemic. Social distancing works to slow the spread of infectious diseases and <a href="https://www.cdc.gov/coronavirus/2019-ncov/need-extra-precautions/what-you-can-do.html" target="_blank">is working for COVID-19</a>. Many people will <a href="https://www.yalemedicine.org/stories/2019-novel-coronavirus/" target="_blank">need medical help to recover</a>, and social distancing will slow this virus down and give people the best chance to do so.</p>
By Elizabeth Claire Alberts
The future for the world's oceans often looks grim. Fisheries are set to collapse by 2048, according to one study, and 8 million tons of plastic pollute the ocean every year, causing considerable damage to delicate marine ecosystems. Yet a new study in Nature offers an alternative, and more optimistic view on the ocean's future: it asserts that the entire marine environment could be substantially rebuilt by 2050, if humanity is able to step up to the challenge.
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By Zulfikar Abbany
Bread has been a source of basic nutrition for centuries, the holy trinity being wheat, maize and rice. It has also been the reason for a lot of innovation in science and technology, from millstones to microbiological investigations into a family of single-cell fungi called Saccharomyces.
Chemical leavening<p>If you like a little heft in your loaf, you will need a leavening agent.</p><p>For those short on time, you can use baking soda. That's a chemical compound of sodium bicarbonate mixed with potassium bitartrate, or cream of tartar.</p><p>Soda breads have their traditions in parts of eastern and central Europe, and in Ireland and Scotland, with Melrose loaves and "farls."</p><p>They can taste a bit bland, though, and are often considered only as an emergency solution on Sundays. No disrespect intended: They taste just fine fresh from the oven.</p><p>Whether it's chemical or more "natural," leavening relies largely on the production of carbon dioxide.</p><p>When you mix an acid, such as vinegar, buttermilk, yogurt or apple cider, with an alkaline compound like baking soda, you get CO2. That CO2 creates bubbles, which in turn capture steam in the oven and allow a bread to rise.</p><p><span></span>But it's better with yeast. Tastes better, too. It just takes more time. </p>
What is yeast?<p>There are yeasts all around us — on grains, in the air, in biofuels. It even lives inside us, but that's not always a good thing.</p><p><a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1090575/pdf/1471-2334-5-22.pdf" target="_blank">Candida yeast</a> can cause infections of the skin, feet, mouth, penis or vagina if it builds up too much in the body.</p><p>One of the most common yeasts, however, is <em>Saccharomyces cerevisiae</em>. That's <a href="https://www.dw.com/en/an-early-beer-archaeologists-tap-ground-at-worlds-oldest-brewery/a-45480731" target="_blank">"brewer's"</a> or "baker's" yeast.</p><p>You can get fresh baker's yeast, often in 42-gram (1.48-ounce) cubes, or as dried yeast (quick action or active, which requires rehydration) in a sachet of 7 grams.</p><p>There's little difference: One is compressed and the other is dehydrated and granulated. But they do the same thing, essentially. </p><p>Some commercial yeast producers add molasses and other nutrients. But natural yeast has plenty of useful nutrients in it anyway, including B group vitamins, so who knows whether it's good or necessary to add them. </p>
How does yeast work?<p>When you mix flour, yeast and water, you set off a veritable chain reaction. Enzymes in the wheat convert starch into sugar. And the yeast creates enzymes of its own to convert those sugars into a form it can absorb.</p><p>The yeast "feeds" on the sugars to create carbon dioxide and alcohol. The yeast burps and farts, releasing gases into the mix, and that creates bubbles to trap CO2. </p><p>It's a vital fermentation process that breaks down the gluten in the flour and helps make your bread more digestible.</p><p>The yeast cells split and reproduce, generating lactic and carbonic acid, raising the temperature and ultimately adding flavor to the mix.</p><p>The longer you leave the yeast to do its thing, the better for your bread. Time is more important than the amount of yeast. </p><p>In fact, that's an enduring question — how much yeast? I'll use 20 grams fresh yeast for 500 grams of flour. Others say that's enough yeast for 1 kilo. If you are converting a dry-yeast recipe to fresh yeast, some bakers advise tripling the weight. So, if a sachet of dried yeast is 7 grams, your fresh yeast is 21 grams.</p><p><span></span>But that also depends on the flours you are using, temperatures in the bowl and the room, and a host of other things. You'll just have to experiment and see. No number of books (and I've read a stack on bread) will help as much as trial and error.</p>
Wild yeast: Sourdough<p>So, good bread needs time. If you have a lot of time, why not move it up a notch and grow wild yeast — a sourdough starter — in your own home?</p><p>A sourdough starter is not to be mistaken (as it often is) for the leaven, or "mother," "sponge," or <em>levain</em>. That's more a second stage, a descendant of the starter. You take a scoop from your starter and add it to another flour and water mixture when you prepare the dough for a new loaf. </p><p>The sourdough process utilizes yeasts naturally present in flour and … yet more time. A longer fermentation process allows a richer lactic acid bacteria <em>lactobacilli</em> or LAB to evolve, and that can be healthy for your gut microbiome.</p><p>It's simple enough to start a sourdough starter. All you need is flour, warm water and time.</p><p>Some suggest equal measures of whole-grain flour and water at 28 degrees Celsius (82 degrees Fahrenheit), some say room temperature — just don't let the water exceed 40 C or the yeasts will die. Some suggest two parts flour to three parts water. But it's up to you whether you want a drier or wetter starter. You will know only through experimentation. </p><p>Some say you should filter tap water to remove chemicals like fluoride and avoid using water that's boiled and then cooled. Others say that really doesn't matter.</p><p>The main thing is, keep it clean and give it time. Days, weeks, months and years.</p>
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