Is It Safe to Take Chlorella When Pregnant? Benefits Explained

During pregnancy, sometimes green and leafy foods just don’t sound appetizing – and that’s okay!

An aversion to crunchy roughage doesn’t mean the nutrition in green veggies isn’t still important.

Packed with vitamins, minerals, and even protein, chlorella steps up to the plate when you’re not feeling a big ‘ol salad on yours – but is chlorella safe while pregnant?

Chlorella is generally regarded as safe by the US Food and Drug Administration (FDA), and this extends to pregnancy as well. Selecting foods and products that are certified as quality by a third-party company is the best way to keep both you and baby safe.

While chlorella is generally safe for healthy adults, there is limited research when it comes to its effects on pregnancy. Further, some women have concerns about safety, as chlorella is an algae.

I’ll break down the safety, any benefits, and provide some guidance on what to look for when shopping.

Is Chlorella Safe During Pregnancy?

Chlorella is a green algae most often seen as a pill, tablet, or powdered supplement.

This marine-derived supplement shares many similarities to its “cousin” spirulina. For more details on spirulina, check out our dedicated article here.

There are some important differences between spirulina and chlorella, especially when it comes to safety during pregnancy.

Chlorella contains nearly 300% of the recommended daily value (DV) for vitamin A in the form of “provitamin A,”, which is later converted to vitamin A in the body (source: Journal of Pharmacy and Nutrition Sciences).

High concentrations of vitamin A in pregnant mothers is known to cause birth defects (source: Nutrients).

While this certainly sounds scary, there is no evidence that taking chlorella causes birth defects due to vitamin A.

This may be due to the type of “provitamin A” in chlorella being hard for human bodies to use efficiently, making it less risky during pregnancy.

Little research has been conducted to back up this theory, however (source: Journal of Pharmacy and Nutrition Sciences).

Chlorella powder and pills

A small Japanese study found that mothers who took chlorella during their pregnancies had lower risk of anemia, protein wasting, and swelling.

These researchers also found no evidence that vitamin A in chlorella caused any adverse effects (source: Plant Foods for Human Nutrition).

Supplements, whether pill, powder, or tablet, are not regulated by the Food and Drug Administration (FDA). Some supplements are tested by third-party companies to ensure the chlorella is safe, of good quality, and pure.

Many of these certified products are also tested to ensure heavy metals are not present at toxic levels. A couple of examples are:

  • Sun Chlorella (National Science Foundation certified)
  • NOW brand (Good Manufacturing Practices certified)

Just as with other marine-derived products, contamination with heavy metals is a concern when it comes to chlorella.

The best way to ensure the chlorella supplement is safe is by choosing a product that has been tested and certified for safety.

Chlorella may interact with some medications, such as blood thinners, so if you’re taking any prescriptions it is best to discuss any supplements with your medical provider before starting (source: Drugs).

For mothers who are breastfeeding or experiencing leakage of breast milk prior to delivery, chlorella has been reported to tint breast milk green(!)

Though green milk may be a shock at first, the green hue is harmless for both mom and baby (source: Drugs).

Overall, chlorella has been listed as “generally regarded as safe” for healthy adults by the FDA (source: Science Direct). Though little research has been done with regards to chlorella consumption and pregnancy, there has been no evidence to date of birth defects related to the higher vitamin A content.

To ensure safety, it is best to only use dietary supplements from reputable companies and those that undergo third-party quality testing.

A green chlorella smoothie

The Benefits of Chlorella for Pregnant Women

As I mentioned above, chlorella supplements were shown to reduce risk of anemia during the second and third trimesters, as well as protein wasting, and swelling during the third trimester in pregnant women.

These effects are in part thanks to chlorella’s vitamin and mineral content (source: Plant Foods for Human Nutrition).

Similar to spirulina and other algae, chlorella is packed full of protein, including nearly every amino acid!

Chlorella also contains rich amounts of vitamins and minerals including vitamin B12, folate, and iron (source: Journal of Pharmacy and Nutrition Sciences).

All of these nutrients are especially important during pregnancy, as they help support the increase in blood volume needed for the growing baby.

There is also some evidence that chlorella can help another common pregnancy symptom, which is to reduce elevated blood pressure (source: Clinical Nutrition).

Again, echoing spirulina, chlorella is often referred to as a “superfood” due to its concentrated nutrition, however, it is not the most budget-friendly way to get your daily greens. Kale, spinach, and broccoli all contain similar nutrients and are often cheaper.

If you do choose to supplement your diet with chlorella, it is easy to incorporate. Beyond simply popping a chlorella tablet or pill, you could also:

  • Stir a tablespoon or so into a glass of juice
  • Blend chlorella powder into smoothies
  • Mix into your favorite energy bites recipe

Can Chlorella Help With Getting Pregnant or Conception?

In addition to providing necessary nutrients and lowering blood pressure, chlorella is rich in antioxidants.

The antioxidants in chlorella play a role in why the algae is thought to increase fertility or make it easier to conceive.

Conceiving a child becomes more difficult as a woman ages, in part due to an increase in oxidation of the ova, or egg cell. The antioxidants in chlorella may help to decrease this oxidation and improve the chances of successful conception.

Unfortunately, the only study backing up this claim was in birds, so th9ere is no guarantee that the same fertility-boosting effects will happen in humans (source: Indian Veterinary Journal).

Overall, as a compact source of protein, B-vitamins, and iron, chlorella provides nutrients to help you support a healthy pregnancy, though it won’t necessarily help you conceive.

Though chlorella does contain a large amount of “provitamin A,” there have not been any reports of adverse birth effects related to this nutrient and chlorella.

Like all algae and marine plans, chlorella does carry a risk for being contaminated with metals and bacteria from the water.

The best way to ensure safety is to choose a product tested for quality by a third-party company.

This article has been reviewed and approved for publication in line with our editorial policy.

Samantha Broghammer, RD

Samantha Broghammer, RD is a Wisconsin-based registered dietitian and nutrition writer. In addition to contributing to Pregnancy Food Checker, she serves the mental health and wellness population as a clinical dietitian providing medical nutrition therapy to those of all ages, from toddlers through senior citizens.

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