Calcium – Are You Unknowingly Sacrificing Your Bones? (70% Of Pregnant Mums Probably Are)

Nearly 70% of Australian women of reproductive age aren’t getting enough calcium through diet alone (Australia Bureau of Statistics, 2015).

Further to that, 1 in 4 adults are failing to meet their requirements for the sunshine vitamin – vitamin D! (Australian Bureau of Statistics, 2011-12). So it’s safe to say, there is a lot of room for improvement when it comes to boosting intake of these two crucial nutrients for all women, but especially those preparing for pregnancy or currently pregnant!

The tricky thing about calcium, in particular, it is really hard to know if you’re getting enough without a thorough review of your diet by a dietitian or nutritionist, as unfortunately, blood tests do not give any indication you’re getting enough calcium! Vitamin D deficiency is generally easier to identify and can be identified with a simple blood test with your GP or health care provider.

With all that in mind, let’s dive into the importance of both calcium and vitamin D during pregnancy.

What is Calcium?

Calcium is an essential mineral, and you need about 1000 mg per day from age 19-50 years of age as a female, or until you reach menopause when requirements then increase. Many people instantly think of the role calcium plays in building and maintaining healthy bones, which is absolutely true! However, many are not aware of the other roles and functions calcium has in the body, including muscle function and the function of the heart.

Calcium requirements are dynamic across our lifetime, as it is needed in greater quantities during phases of building more bone mass such as in your teenage years and up until about age 25. After this time you stop gaining bone mass stops, it plateaus and then gradually it starts to decline as you age.

Once menopause is reached, on average around age 50 years, the loss of estrogen means your bones are less protected and there are more losses of calcium from bones, so recommendations for calcium increase again to try to minimise these losses and prevent the development of osteoporosis, which is the weakening of the bones leading which can lead to an increased risk of bone fractures.

Requirements go from 1300 mg during your teen years, dropping to 1000 mg per day during adulthood and rising again to 1300 mg per day once menopause is reached. Interestingly, there are no significant changes to calcium requirements during pregnancy, more on this later in this article.

How Do You Get Calcium?

The best way to achieve adequate calcium is through consuming dairy foods such as milk, yoghurt and cheese. Dairy alternatives such as soy, oat or almond milk if being used on a vegan diet or due to dairy intolerance should be fortified with at least 120 mg of calcium per 100 mL (check the nutrition label!) to be a suitable replacement for dairy in terms of calcium content. Non-dairy sources of calcium include bony fish such as sardines or tinned salmon or calcium-fortified tuna as well tofu. Other sources of calcium are typically making contributions of less than 100 mg per serving which include green vegetables, dried figs, nuts such as almonds, tahini & sesame seeds and chickpeas.

As is mentioned earlier, unfortunately, there is no simple way to know if you’re getting enough calcium through your diet, as blood tests will generally show normal calcium levels as your body does a great job of tightly regulating the amount in your bloodstream often at the expense of your bones, which is the biggest storage site of calcium in the body. Which means, if you aren’t getting enough calcium via your diet, your body will breakdown some bone to release calcium into the bloodstream to ensure your nerves, muscles and heart are working correctly.

Many people have no idea this happening to them, unless they undergo a bone mineral density scan or a DEXA scan via their health care provider, which is not considered routine for most people.

Can Calcium Supplements Help?

Supplements can be a great option, because the help fill any gaps from your diet are ensure you are consistently meeting your needs day in and day out.

Here are some tips on what to look for when looking for a calcium and vitamin D supplement:

  • Choose calcium citrate forms as these are known to be best absorbed!
  • Break up your calcium supplement dosage across your meals throughout the day, this helps boost absorption too.
  • Ensure your calcium supplement also contains vitamin D3, this will also help optimise absorption

Also, be sure to not combine your calcium supplements with iron or zinc containing supplements to maximise absorption, as these nutrients will compete in your small intestine and result in not getting the most out of your supplement!

What is Vitamin D?

Vitamin D is a fat-soluble vitamin that is required to help absorb calcium in the body. Vitamin D also plays some important roles when it comes to our health supporting immune and hormone function too.

Vitamin D is classically known as the sunshine vitamin as our body makes it when our bare skin is in direct sunlight, although some dietary sources can provide vitamin D such as mushrooms exposed to sunlight, some fish such as cod, sardines and salmon and egg yolks.

Vitamin D deficiency is usually asymptomatic although some people do feel fatigue with vitamin D deficiency. Your GP can be easily identify Vitamin D deficiency with a simple blood test.

If you are, your GP will most likely suggest you use a supplement to correct poor vitamin D levels and then re-check your levels to ensure they have come back into normal range.

It is also pretty normal to see some seasonal variation between winter and summer in particular, so keep this in mind when assessing vitamin D status.

Some People are at an Increased Risk of Vitamin D deficiency:

  • People who spend daylight hours indoors.
  • People who wear religious headdresses or other clothing that covers the skin, preventing direct sunlight exposure on the skin.
  • People who have darker or more pigmented skin, as higher levels of melanin can contribute to poorer vitamin D status despite sunlight exposure.
  • People who avoid dairy products due to an allergy or intolerance, or those who are breastfeeding an infant with a diagnosed cow’s milk allergy or intolerance and are avoiding these products in their diet.
  • People who have a malabsorptive conditions such as Coeliac disease, inflammatory bowel disease or have undergone weight loss surgery.
  • Post-menopausal women or people with primary ovarian insufficiency (POI).
  • People who follow a vegan diet might be at an increased risk of poor vitamin D status.

As vitamin D is a fat-soluble nutrient, there is such a thing as too much, as our bodies are unable to remove it easily if we supplement too much for example, as any excess will be stored in your fat. So make sure you speak to your healthcare provider about your vitamin D status and supplementation plan and ensure appropriate measures are taken to protect yourself from the potential harms of the sun too!

Calcium and Vitamin D Demands During Pregnancy

During pregnancy & breastfeeding, calcium and vitamin D requirements actually remain unchanged to pre-conception needs, so all throughout this time period your target for calcium is 1000 mg per day and vitamin D is 1000 IU per day, unless you’re advised otherwise by your health care provider.

Interestingly, during pregnancy it is understood that calcium absorption in the small intestine is better from food, similar to iron. Meaning pregnant women are getting more calcium uptake from the foods they were usually eating anyway, which is pretty handy, especially when you need to build a whole new skeleton of your future baby in just 9 short months!

Building a whole mini skeleton does require calcium, but no extra due to this increase in absorption, however with close to 70% of women not getting enough calcium before or after pregnancy, it is safe to say chances are pregnant women are not either! This means during pregnancy, your bones could be sacrificing themselves to build your baby’s skeleton which could increase your future risk of having low bone mineral density and osteoporosis in your older adult years.

So, optimising your calcium intake through diet and where gaps are identified through a customised and targeted supplementation regime is key! Many pregnant women rely on their prenatal supplement to fill in all their dietary gaps, but, it is uncommon for a prenatal supplement to contain a high dosage of calcium as they often contain other nutrients that are higher priority such as iron and zinc which would compete with each other for absorption.

Ensuring you get enough calcium each day is important, aim for about 250 mL of milk or calcium-fortified milk alternative, about 200 g or ¾ cup of dairy based yoghurt and 40 grams of cheese to reach your 1000 mg per day target. If you avoid dairy for ethical, religious or health-related reasons, consider speaking with a prenatal dietitian & nutritionist to discuss how you can support adequate calcium in your diet and assess your needs for a potential supplement recommendation to bridge this gap to ensure you and baby are healthy!

As mentioned already, vitamin D requirements also don’t change throughout pregnancy, staying at the 1000 IU (international units) per day from pre-conception through to breastfeeding. However, given 1 in 4 people are vitamin D deficient and based on your blood results you may need more than this to correct the deficiency and get back into a healthy range, as 1000 IU per day will simply maintain your vitamin D status, not improve it.

If you have concerns about your vitamin D status and whether a supplementation regime might be right for you, speak with your health care provider.

Pregnancy Concerns Associated with Low Calcium and Vitamin D Levels

There are some particular pregnancy related health concerns that may change your change your calcium demands, particularly having a history of high blood pressure, or hypertension or being identified as high-risk for developing pre-eclampsia, which is often characterised by high blood pressure but can have a significant impact on the kidneys and liver and can pose a serious risk to both your own health and your babies if not managed quickly and appropriately by your obstetrician or medical team.

Research shows that improving calcium status, typically through supplementation as well as diet, may reduce the risk of developing pre-eclampsia and associated complications with hypertensive disorders in pregnancy as outlined by RANZCOG (2014), the national body of Obstetricians & Gynaecologists for Australia and New Zealand.

Vitamin D status is important to keep top of mind during pregnancy, as poor vitamin D status amongst mothers has been linked to an increased risk of babies developing asthma, eczema & allergies, for example (Allen et al., 2013; Zhenzhen, Zhang & Yu et al., 2016).

Please discuss your individual health circumstances with your health care team and providers before starting or changing your supplementation or diet plan.

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