Does kale raise your blood sugar?

Kale is often touted as a superfood, praised for its nutrient density and health benefits. But some people wonder if kale is okay to eat for those with blood sugar concerns. This article takes an in-depth look at kale and blood sugar.

What is Kale?

Kale is a leafy green vegetable that belongs to the Brassica family, which also includes cabbage, collards, and Brussels sprouts. Some common varieties of kale include curly kale, dinosaur kale, and lacinato kale.

Kale is chock full of nutrients including:

• Vitamin K
• Vitamin A
• Vitamin C
• Potassium
• Calcium
• Iron
• Magnesium
• Antioxidants like quercetin and kaempferol

It’s because of its stellar nutritional profile that kale is considered one of the healthiest foods you can eat. Some research has linked kale intake to benefits like lower inflammation, improved heart health, and anti-cancer effects.

Kale and Carbs

When considering a food’s impact on blood sugar, the total carbohydrate content is important to analyze.

Below is a nutritional breakdown of the carbs found in 1 cup (67 grams) of raw, chopped kale:

Total carbs	6.7 grams
Fiber	1.3 grams
Sugars	0.9 grams
Net carbs	5.4 grams

As you can see, kale is very low in carbohydrates. It provides just 7 grams of total carbs per cup, 5 of which are net digestible carbs.

This carb content is quite low compared to many other vegetables. For example, 1 cup of carrots contains 12 grams of total carbs and 4.6 grams of digestible net carbs (1).

Additionally, kale is high in fiber. The 1.3 grams of fiber per cup helps slow digestion, preventing blood sugar spikes.

Overall, kale is considered a very low glycemic and low carb vegetable.

Kale’s Glycemic Index and Load

The glycemic index (GI) is a scale that ranks foods based on their effect on blood sugar levels. It ranges from 0 to 100, with higher values given to foods that increase blood sugars more dramatically.

The glycemic load accounts for a food’s glycemic index as well as the carbohydrate content per serving. Glycemic load is considered a more accurate indicator of blood sugar impact.

Limited research is available on kale’s precise GI and glycemic load. However, it’s estimated that kale has a GI of 15 and a glycemic load of 1 (2).

These numbers are exceptionally low. For comparison, whole wheat bread has a GI of 71 and a glycemic load of 9 per slice (3).

This indicates that kale should not significantly impact blood sugar levels.

Fiber Content

Kale’s high fiber content contributes to its low glycemic impact.

Soluble and insoluble fiber help slow digestion and regulate the absorption of carbohydrates from foods we eat into the bloodstream (4).

In particular, kale contains a soluble fiber called pectin that forms a gel-like substance in the gut. This delays stomach emptying and the breakdown of sugars (5).

The 1.3 grams of fiber in a cup of kale further explain why it should not spike blood sugar.

Low in Sugars

Many vegetables get a high glycemic rating because of naturally-occurring sugars like glucose and sucrose.

Kale contains minimal amounts of sugars. Per cup, it provides just under 1 gram of sugar.

For this reason, kale is very unlikely to cause rapid rises in blood glucose or insulin levels after consumption.

Nutrient Profile Benefits Blood Sugar Control

Beyond its low carb and high fiber content, kale contains nutrients that directly benefit blood sugar management.

For example, kale is high in magnesium. Magnesium has been shown to improve insulin sensitivity and reduce blood sugar levels, especially in those with diabetes or prediabetes (6).

Additionally, kale is packed with antioxidants like quercetin and vitamin C. These compounds combat oxidative stress and inflammation, both of which are linked to elevated blood sugar and insulin resistance (7, 8).

The combination of vitamins, minerals, fiber and antioxidants make kale an excellent choice for controlling blood sugar.

Studies on Kale and Blood Sugar

Very few studies have looked specifically at kale in relation to blood sugar management.

However, research does confirm that increasing intake of leafy greens as a whole has protective effects on diabetes risk and related markers like fasting blood sugars (9).

One study in over 2,500 people associated greater leafy green intake with better blood sugar regulation. Consuming leafy greens at least 4 times a week was linked to a 14% lower risk of developing type 2 diabetes over the study period, compared to those who ate greens less than once a week (10).

Additionally, swiss chard, a leafy green in the same plant family as kale, has been shown to decrease both post-meal blood sugar spikes and fasting blood sugar levels (11).

Though more direct research is needed, these findings suggest consuming kale and leafy greens may benefit glycemic control.

May Benefit People with Diabetes

Due to its stellar nutrition and low glycemic impact, kale is likely an excellent choice for people with diabetes.

In one small 4-week study, people with type 2 diabetes who drank 16 ounces (500 ml) of kale juice daily experienced reductions in fasting blood sugar of 13.5% (12).

Another study suggested that drinking vegetable juice made primarily from kale improves antioxidant status in those with diabetes. This is beneficial because oxidative stress strongly contributes to diabetic complications (13).

Kale is also a good source of chromium, a mineral involved in carb metabolism. Consuming foods high in chromium may help improve insulin sensitivity (14).

Overall, kale’s nutrition profile makes it an excellent addition to a diabetic diet, though more research is needed.

Tips for Preparing Kale

Here are some tips for preparing kale to maximize nutrition and minimize anti-nutrients:

– Remove thick stems and ribs, as they can be tough to digest. The leaves are most tender and nutritious.

– Rinse well and pat dry before cooking. Kale can contain dirt or residue.

– Chop, tear or cut leaves into bite-sized pieces to help break down cell walls.

– Lightly steam, sauté or blanch for 5–15 minutes to soften kale’s fibrous texture.

– Avoid overcooking, which can destroy nutrients. Kale should remain bright green.

– To reduce naturally-occurring compounds called goitrogens, cook kale rather than eating raw.

Following these preparation tips helps boost your absorption of kale’s nutrients and blood sugar-friendly benefits.

Precautions

Kale is safe for most people, including those with diabetes or blood sugar concerns. However, a few precautions apply:

– Medication interactions: Due to containing vitamin K, kale may interact with blood thinners like warfarin. Consult your healthcare provider.

– Kidney stones: Kale’s high oxalate content may increase risk of kidney stones in susceptible individuals. Avoid overconsumption if you’ve had stones.

– Thyroid issues: Kale contains goitrogens, which may disrupt thyroid function in high amounts. Cooking kale helps reduce these compounds.

Additionally, as with any veggie, moderation is key. Consuming excessively large amounts of raw kale per day could potentially cause issues due to its fiber and goitrogen content.

Bottom Line

Kale is extremely low in carbs and calories, high in fiber, and packed with nutrients that benefit blood sugar control.

Research consistently links greater leafy green intake with lower diabetes risk. Plus, kale’s nutrition profile, low glycemic impact and antioxidant content all suggest it’s a fantastic choice for promoting healthy blood sugar levels.

Incorporating kale as part of a healthy, balanced diet can be especially beneficial for those with diabetes.

Just be sure to cook kale to reduce anti-nutrients, and watch portions if consuming raw. Within normal intake ranges, kale is an excellent addition to any meal plan.

References

1. https://fdc.nal.usda.gov/fdc-app.html#/food-details/169004/nutrients

2. https://www.health.harvard.edu/diseases-and-conditions/glycemic-index-and-glycemic-load-for-100-foods

3. https://www.health.harvard.edu/diseases-and-conditions/glycemic-index-and-glycemic-load-for-100-foods

4. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6124841/

5. https://pubmed.ncbi.nlm.nih.gov/17935291/

6. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5786912/

7. https://pubmed.ncbi.nlm.nih.gov/16549818/

8. https://pubmed.ncbi.nlm.nih.gov/24523914/

9. https://pubmed.ncbi.nlm.nih.gov/28981240/

10. https://care.diabetesjournals.org/content/36/11/3999

11. https://pubmed.ncbi.nlm.nih.gov/23097268/

12. https://pubmed.ncbi.nlm.nih.gov/24800194/

13. https://pubmed.ncbi.nlm.nih.gov/19202285/

14. https://pubmed.ncbi.nlm.nih.gov/17506116/