Is Flaxseed (Linseed) Safe During Pregnancy? Benefits vs Risks

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Written by Gina Wagg BA, Dip.

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Flaxseed is a highly nutritious food with many health benefits. However, its use during pregnancy is controversial.

Flax seeds should only be eaten in small amounts when pregnant, and flaxseed oil should be avoided during pregnancy and breastfeeding. Studies are limited, though existing research suggests that flax may have unwanted hormonal effects in pregnant women.

Flaxseed is also called ‘Linseed’, but we’ll refer to it as flaxseed throughout this article.

Let’s look at what the studies say, and what you need to know to stay safe and healthy around flaxseed and flaxseed oil.

Is It Safe to Eat Flaxseed During Pregnancy?

There is conflicting advice concerning flaxseed during pregnancy.

Overall, it is not recommended to use flaxseed or flaxseed oil during pregnancy, despite their many health benefits (Source: Mayo Clinic).

The National Center for Complementary and Integrative Health in the USA also advises pregnant women to avoid flax seed (source: NIH).

Flaxseed contains more lignans than most other foods. Lignans are phytoestrogens that have an estrogenic or anti-estrogenic effect (source: Academy of Nutrition and Dietetics).

Any food with such effects should be treated with caution by pregnant women. Studies into flaxseed or linseed during pregnancy are limited, and such estrogenic effects may adversely affect pregnancy (source: AHS).

A 2007 animal study also found a potential correlation between consuming flaxseed when pregnant, and offspring subsequently being more susceptible to breast cancer (source: Journal of Reproductive Toxicology).

However, it was not conclusive, and nothing similar has yet been studied in humans.

In Canada, the advice differs. It’s suggested that pregnant women reduce or limit their intake to food amounts of flaxseed rather than to avoid it completely, up to a maximum of 45g a day.

The advice to avoid flaxseed oil completely is the same, however (source: Alberta Health Services).

As with many foods in pregnancy, it comes down to your personal choice.

If, for example, you’re following a vegan or vegetarian diet then you might want to eat small amounts of flaxseeds for their nutrient content, which we’ll discuss later in this article.

If you feel that you could get the same nutrients from other sources during pregnancy (by eating fish for the omega-3s, for example), then you may wish to avoid flaxseed completely for the duration of your pregnancy.

There are two types of flaxseed: brown and golden. Flaxseed is also called linseed, and can come as whole seeds, ground or milled seeds, or powders.

Flaxseed can hide in many foods, so check labeling carefully. Here are some common foods that may contain flaxseed or linseed:

  • Breads
  • Muffins
  • Pancakes
  • Crackers
  • Cereals
  • Pasta
  • Energy bars
  • Superfood salad sprinkles
  • Superfood powder mixes (for smoothies and soups)
  • Meatless meal products
  • Snack foods
  • Cooking oils
  • Salad oils
  • Dips and sauces
  • Salad dressings
  • Foods with ‘fiber added’
flaxseeds on a spoon

Are There Benefits of Eating Flax Seed When Pregnant?

Flaxseeds are an excellent source of the omega -3 fatty acid called α-linolenic acid (ALA) which are essential for all of us, and more so when you are pregnant.

This is because omega-3s help aid the brain development of the fetus, particularly during the first trimester (source: Reviews in Obstetrics and Gynecology).

However, there are other foods that also contain ALA in generous amounts, so flaxseed isn’t your only option in pregnancy.

The omega-3s in flaxseed also are not the same as the long-chain omega-3 fatty acids found in food like fish (source: NHS).

To get your omega-3s safely, choose other foods such as oily fish or walnuts, which have no known adverse effects during pregnancy.

Flaxseeds can help keep your blood sugar in check. However, there are safer alternatives that do the same job, such as oats, and protein-rich foods like turkey, chicken, and fish.

Can Flaxseed Help with Pregnancy Constipation?

Flaxseeds are definitely an excellent way to help with constipation because they are high in soluble fiber (source: PubMed).

However, because it is not recommended to eat flaxseeds while pregnant, you don’t necessarily have to turn to them to combat constipation.

You might want to choose other foods to support you safely, such as prunes, chia seeds, pulses, fresh fruits, and vegetables.

Are There Side Effects of Flax Seed When Pregnant?

Flaxseed can bring side effects, particularly if it is eaten without enough water.

As flaxseed is very high in fiber, you need to make sure you’re getting enough liquid in your body to digest flaxseed.

If you eat too much fiber-rich food like flaxseed and don’t drink enough water, you could experience tummy troubles, such as bloating, gas, or diarrhea (source: Harvard).

Since you’ll likely be more prone to this during pregnancy anyway, it may be another reason to skip flaxseed until after your baby is born.

If you are taking medication, there are a number of side effects that you definitely want to be aware of.

These can range from a decrease in blood clotting, to lower blood pressure, or lower blood sugar levels (source: Mayo Clinic).

Even if you choose to eat some flaxseed when pregnant, you should still contact your health professional to make sure it’s right for you and isn’t contraindicated with other medications you might be taking.

Can I Eat Raw Flaxseed When Pregnant?

Raw flaxseed has a lot of fiber. It also contains very small amounts of cyanide compounds, as do other foods such as raw chickpeas, cashews or almonds (source: Journal of Food Additives and Contaminants).

Therefore, it isn’t a good idea to eat raw flaxseed, even if you’re not pregnant.

However, our bodies are able to metabolize some of these compounds, so small amounts (up to 2 tablespoons) can be fine (Source: BlockMD), as long as you’re not pregnant.

Heat breaks down cyanide compounds, so if you are concerned about others who are eating flaxseed, just use flaxseed or flax meal in hot soups or sauces.

You can also soak them overnight. In the morning they’ll form a thick and gloopy mixture which is normal. You can then blend them into smoothies or soups, or make crackers with them.

Soaking and blending them is another way to make them easier to digest.

If you really want to eat a small amount of flaxseeds, or you are preparing them for someone else, you can blitz the dry seeds in a blender or coffee grinder to make flax meal, which is easier to digest.

Make sure though that you’re having flax meal along with lots of liquids.

Raw flaxseed is best stored in an airtight container in the refrigerator, as it can go rancid quickly.

flaxseed or linseed oil with seeds

Is Flaxseed Oil Safe When Pregnant?

Unlike flaxseed as a food, flaxseed oil is not recommended in pregnancy, and much of the existing pregnancy advice warns against using it (sources: Mayo Clinic, AHS).

Flaxseed oil can help treat digestive issues such as constipation and diarrhea, as well as reduce inflammation. It can also improve the condition of your skin, and could even benefit your heart.

Again, this doesn’t mean it’s a good choice when you’re pregnant.

Avoiding flaxseed oil may be more important in later stages of pregnancy. A recent study found that you may be four times more likely to give birth prematurely if you consume flaxseed oil in the last two trimesters of your pregnancy (Source: SD).

The percentage of women with premature births went from 2 to 3 percent up to 12 percent if they consumed flaxseed oil during the second or third trimester.

Even if you’re in very early pregnancy / the first trimester, you should still avoid consuming flaxseed oil.

Flaxseed Oil on the Skin When Pregnant

Caution is not only advised against consuming flaxseed oil as a food, but there may be issues when applied to the skin, too.

If you are scheduled to have a Caesarean or any other type of surgery, you need to know that flaxseed oil may increase the risk of bleeding.

If you do use a small amount, stop using it at the very least by 2 weeks before your scheduled surgery (Source: WebMD).

For this reason, it’s wise to check labels when choosing skincare products, as many creams, lotions, soaps and shampoos contain flaxseed or linseed oil.

Some examples of products with flaxseed or linseed oil include:

  • Facial oils
  • Bath oils
  • Face creams
  • Body lotions
  • Shampoos
  • Moisturizers
  • Skin creams (especially to treat eczema or psoriasis)
  • Anti-aging creams and lotions
  • Hair oils
  • Scalp oils
  • Body sprays

In conclusion, it is best to avoid flaxseed, flaxseed oil, and any products containing flaxseed while pregnant.

If you really want to eat flaxseed while pregnant (for example, if you follow a plant-based diet), then you can do so in small amounts – and make sure the flaxseed is both kept fresh and is not raw.

If you have already eaten flaxseed when pregnant, it’s unlikely to have done any harm in food amounts, though you may wish to avoid it for the remainder of your pregnancy.

Check the labels of crackers, cereals and cereal bars, and superfood mixes, as many can contain flaxseed.

It’s also a good idea to check with your doctor, because the potential risks (and unknowns) outweigh the benefits, so educate yourself and go for the safest options to have a healthy, happy pregnancy!