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30 million people live with diabetes in the United States, and over twice as many live with prediabetes — with numbers constantly on the rise (1, 2).

Flax seeds — and flaxseed oil — boast many health-promoting compounds with the potential to lower blood sugar levels and delay the development of type 2 diabetes (3).

This article reviews the benefits and downsides of eating flax seeds and flaxseed oil if you have diabetes.

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Flax seeds (Linum usitatissimum) are one of the world’s oldest crops. They have been cultivated for their use in both the textile and food industries since about 3000 B.C. (4).

The seeds comprise about 45% oil, 35% carbs, and 20% protein and have exceptional nutritional characteristics (5).

One tablespoon (10 grams) of whole flax seeds packs (6):

  • Calories: 55
  • Carbs: 3 grams
  • Fiber: 2.8 grams
  • Protein: 1.8 grams
  • Fat: 4 grams
  • Omega-3 fatty acid: 2.4 grams

Flax seeds are one of the best plant sources of the omega-3 fatty acid alpha-linolenic acid (ALA), an essential fatty acid that you must obtain from foods, as your body can’t produce it.

They also have enough omega-6 fatty acids to provide an excellent omega-6 to omega-3 ratio of 0.3 to 1 (4).

Their carb content consists mostly of fiber — both the soluble and insoluble kinds.

Soluble fiber forms a viscous mass when mixed with water, helping manage blood sugar levels. On the other hand, insoluble fiber — which is not water-soluble — acts by increasing fecal bulk, helping prevent constipation (4).

Finally, flax seed contains a significant amount of digestible, high-quality protein and an amino acid profile comparable to that of soybean (4, 5).

Difference between flax seeds and flaxseed oil

Flaxseed oil is extracted from dried flax seeds, either by pressing them or solvent extraction.

Thus, flaxseed oil consists purely of flax seeds’ fat content, whereas its protein and carb contents are virtually nonexistent — meaning that it also doesn’t provide any fiber.

For example, 1 tablespoon (15 ml) of flaxseed oil provides 14 grams of fat and 0 grams of protein and carbs (7).

On the other hand, the same amount of whole flax seeds offers 4 grams of fat, 1.8 grams of protein, and 3 grams of carbs (6).

However, due to its higher fat content, flaxseed oil delivers a higher amount of ALA than the seeds (4, 8).

Summary

Flax seeds and flaxseed oil are an excellent plant source of omega-3 fatty acids, principally ALA. Flax seeds are especially nutritious, as they also provide a good amount of protein and fiber.

Both flax seeds and flaxseed oil have been shown to have a positive effect on diabetes, as they may improve many of its risk factors.

Flax seeds may promote blood sugar control

Maintaining healthy blood sugar levels is crucial for people with diabetes, and fiber plays a major role in achieving this.

Due to their high fiber content, flax seeds are considered a low-glycemic food. This means that consuming them won’t spike your blood sugar levels and instead cause them to rise steadily, promoting blood sugar control.

This effect can partly be attributed to their soluble fiber content, specifically mucilage gums, which slow food digestion and decrease the absorption of certain nutrients like sugar (4, 9).

One 4-week study in 29 people with type 2 diabetes found that consuming 10 grams of flaxseed powder per day reduced fasting blood sugar by 19.7%, compared with the control group (10).

Similarly, in a 3-month study in 120 people with type 2 diabetes, those who consumed 5 grams of flaxseed gum daily with their food experienced a fasting blood sugar reduction of about 12%, compared with a control group (11).

What’s more, a 12-week study in people with prediabetes — those who are at risk of developing type 2 diabetes — observed similar results in those who consumed 2 tablespoons (13 grams) of ground flax seeds daily (12).

Though flax seeds seem to benefit blood sugar control, research shows that the same cannot be said for flaxseed oil (13, 14).

Flax seeds and flaxseed oil may improve insulin sensitivity

Insulin is the hormone that regulates blood sugar.

If your body has difficulties responding to insulin, it requires greater amounts of it to lower your blood sugar levels. This is called insulin resistance, and it’s a risk factor for type 2 diabetes (1).

Meanwhile, insulin sensitivity refers to how sensitive your body is to insulin. Improving it can help prevent and treat type 2 diabetes (15).

Flax seeds contain high amounts of lignan, which acts as a powerful antioxidant. Antioxidants are believed to improve insulin sensitivity and slow the development of diabetes (4, 16).

The lignans in flax seeds predominantly consist of secoisolariciresinol diglucoside (SDG). Animal studies suggest that SDG has the potential to improve insulin sensitivity and delay the development of both type 1 and 2 diabetes (3, 17, 18).

Still, human studies have not been able to confirm this effect, and further research is needed (16, 19).

On the other hand, ALA from flaxseed oil has also been linked to improved insulin sensitivity in both animals and humans.

In fact, one 8-week study in 16 people with obesity observed an increase in insulin sensitivity after they received a daily oral dose of ALA in supplement form (20).

Similarly, studies in rats with insulin resistance found that supplementing with flaxseed oil improved insulin sensitivity in a dose-dependent manner, meaning that the larger the dose, the greater the improvement (21, 22, 23).

May reduce your risk of heart disease

Diabetes is a risk factor for heart disease and stroke, and both flax seeds and flaxseed oil have been shown to help protect against these conditions for multiple reasons, including their fiber, SDG, and ALA contents (24, 25, 26).

Soluble fibers like the mucilage gum in flax seeds have cholesterol-lowering properties.

That’s because their capacity to form a gel-like substance affects fat metabolism, thus decreasing cholesterol’s absorption (27).

One 7-day study in 17 people found that flaxseed fiber lowered total cholesterol by 12% and LDL (bad) cholesterol by 15%, compared with the control group (28).

Additionally, flax seeds’ main lignan SDG acts as both an antioxidant and a phytoestrogen — a plant-based compound that imitates the hormone estrogen.

While antioxidants have cholesterol-lowering properties, phytoestrogens play an important role in blood pressure reduction (29, 30).

One 12-week study in 30 men with high blood cholesterol levels determined that those who received 100 mg of SDG experienced a decrease in LDL (bad) cholesterol levels, compared with the control group (31).

Finally, the omega-3 fatty acid ALA also has potent anti-inflammatory effects.

Research suggests that it may help treat — and even regress — clogged arteries, which are a risk factor for stroke (32, 33).

What’s more, studies in people with high blood pressure have found promising results when participants consumed about 4 tablespoons (30 grams) of milled flax seeds per day.

They observed a reduction of 10–15 mm Hg and 7 mm Hg in systolic and diastolic blood pressure (the top and bottom numbers of the reading), respectively, compared with the control groups (34, 35).

Summary

Flax seeds and flaxseed oil are rich in soluble fiber, ALA, and SDG, all of which may reduce heart disease risk and improve blood sugar control and insulin sensitivity.

Though flax seeds and flaxseed oil have multiple health benefits, they may interact with some medications that are used to regulate blood sugar and cholesterol levels (36).

This especially applies to flaxseed oil, as it has a higher omega-3 content.

For example, omega-3 fatty acids have blood-thinning properties, which may increase the effect of blood-thinning drugs, such as aspirin and warfarin, which are used to prevent blood clots (37).

Also, omega-3 fatty acid supplements may interfere with blood sugar regulation by decreasing blood sugar levels.

This means that they might lower blood sugar too much, necessitating an adjustment to your dosage of blood-sugar-lowering medications.

Still, the omega-3 fatty acids in flax seed or flaxseed oil supplements may make some cholesterol-lowering medications more efficient (36).

In any case, you should consult your healthcare provider before adding flax seeds or flaxseed oil to your daily routine.

Summary

Eating flax seeds or flaxseed oil may interfere with medications used to manage blood sugar and blood cholesterol levels. Thus, you should be cautious before consuming them.

Flax seeds and flaxseed oil are very easy to cook with. They can be consumed whole, milled, and roasted, or as an oil or flour (24).

However, whole flax seeds may be harder to digest, so try sticking to the ground or milled versions if you’re looking for something other than oil.

You can also find them in numerous food products, such as baked goods, juices, dairy products, and even beef patties (4, 38).

Also, you can incorporate them into almost everything you cook, including as a thickening agent for soups and sauces or in your favorite coating mixture for a nice crust.

One simple and delicious way to enjoy flaxseeds is to prepare flax crackers.

Here’s what you need:

  • 1 cup (85 grams) of ground flax seeds
  • 1 tablespoon (10 grams) of whole flax seeds
  • 2 teaspoons of onion powder
  • 1 teaspoon of garlic powder
  • 2 teaspoons of dried rosemary
  • 1/2 cup (120 ml) of water
  • pinch of salt

Mix the dry ingredients in a small bowl. Then pour the water over it and use your hands to form a dough.

Place the dough between two pieces of parchment paper and roll it to your desired thickness. Remove the top portion of the parchment paper and cut the dough into squares. This recipe yields about 30 crackers.

Place the dough on a baking sheet and bake it at 350°F (176°C) for 20–25 minutes. Let it cool and then serve them with your favorite dip.

As for flaxseed oil, you can add it to dressings and smoothies, or you can find flaxseed oil capsules in stores and online.

Summary

Flax seeds and flaxseed oil can be eaten whole, ground, as oil, or in capsules, as well as added to sweet and savory dishes alike.

Flax seeds and flaxseed oil have multiple health benefits that may help people with diabetes manage the condition.

Since they’re rich in fiber, omega-3 fatty acids, and unique plant compounds, they may improve blood sugar control, insulin sensitivity, and reduce risk factors for heart disease.

However, you should be mindful before consuming them, as they may interact with other medications prescribed for the treatment of diabetes.