It is one of the foods with the highest nutritional density on the planet
Kale is in the same family as cruciferous vegetables like cabbage, broccoli, cauliflower, and Brussels sprouts.
Its leaves can be green or purple, depending on the type, and also be smooth or wavy. The most common variety has curly, green leaves and a tough, stringy stem.
One cup of raw kale (about 67 grams) contains (1):
- Vitamin A (in the form of beta-carotene): 206% of the recommended daily amount (RDA).
- Vitamin K: 684% of the RDA.
- Vitamin C: 134% of the RDA.
- Vitamin B6 9% of the RDA.
- Manganese: 26% of the RDA.
- Calcium: 9% of the RDA.
- Copper: 10% of the RDA.
- Potassium: 9% of the RDA.
- Magnesium: 6% of the RDA.
- It also contains 3% or more of the RDA of vitamin B1 (thiamine), vitamin B2 (riboflavin), vitamin B3 (niacin), iron and phosphorus. This includes 33 calories, 6 grams of carbohydrates (2 of which are fiber), and 3 grams of protein.
Kale has very little fat, but most of it is alpha linoleic acid, an omega-3 fatty acid.
2. Includes powerful antioxidants, like quercetin and kaempferol
The antioxidants in kale include beta-carotene, vitamin C, and various flavonoids and polyphenols (2).
In addition to preventing oxidative damage to cells, some antioxidants have other very important functions. For example, quercetin and kaempferol (included in kale) have cardioprotective, blood pressure normalizing, anti-inflammatory, antiviral, antidepressant and anticancer effects, among others (3, 4, 5).
Bottom Line: Kale contains many powerful antioxidants, including quercetin and kaempferol, which have numerous health benefits.
3. It is an excellent source of vitamin C
Kale has more vitamin C than most other vegetables. For example, it contains four times more than spinach (6).
This makes it one of the best sources of this vitamin. A cup of raw kale even contains more vitamin C than an orange (7).
Bottom line: Kale is very high in vitamin C. A cup contains it in a higher proportion than an orange.
4. Helps lower cholesterol
One of the functions of cholesterol in the body is to serve as a raw material for the secretion of bile acids, which help digest fats.
The liver converts cholesterol into these acids, which are then released into the digestive system each time fatty foods are eaten.
When the fat has been absorbed and the bile acids served their purpose, they are reabsorbed in the digestive system to be reused.
There are substances called bile acid sequestrants that can bind them in the digestive system and prevent their reabsorption. And this reduces the total amount of cholesterol in the body.
And kale contains bile acid sequestrants, which can lower cholesterol levels and, in the long run, lower the risk of heart problems (8).
In this sense, a study found that the consumption of kale juice for 12 weeks raised HDL cholesterol (the "good") by 27% and lowered LDL levels by 10%, at the same time that it improved levels antioxidants (9).
Additionally, according to other research, steaming cabbage dramatically increases the effect of bile acid sequestrants. In fact, steamed kale is 43% as potent as cholestyramine, a cholesterol-lowering drug (10).
Bottom line: Kale contains substances that bind bile acids, lowering cholesterol levels in the blood. Steamed cabbage is even more effective.
5. It is one of the best sources of vitamin K on the planet
One cup of raw kale contains almost seven times the recommended daily amount of vitamin K, critical for blood clotting.
The form of the vitamin present in this vegetable is K1, which is different from K2, which is usually found in fermented soy foods and some animal products. It is useful for preventing heart problems and osteoporosis (11).
Bottom line: Vitamin K is an important nutrient involved in blood clotting. One cup of kale contains seven times the recommended daily amount of this vitamin.
6. Contains various anticancer substances
Kale contains components that are believed to help fight cancer. This includes sulforaphane, a substance that has been shown to fight cancer formation at the molecular level (12, 13). It also contains indole 3-carbinol, another component that appears to prevent cancer (14).
And in general, some studies have shown that cruciferous vegetables like kale can significantly lower the risk of certain cancers, although the evidence in humans is not conclusive (15, 16).
Bottom Line: Kale contains substances that have been shown to help fight cancer in laboratory tests and in animal studies, but the evidence in humans is not yet conclusive.
7. It is very high in beta carotene
Kale is often said to be high in vitamin A, but this is not exactly true. It is high in beta-carotene, an antioxidant that the body can convert into that vitamin and, thus, raise its blood levels (17).
Bottom line: Kale is high in beta-carotene, an antioxidant that the body can convert into vitamin A.
8. It is a good source of minerals that people do not get enough of
Kale is a great plant source of calcium, very important for bone health and for various cell functions.
It also has a decent presence of magnesium, which is generally not sufficiently incorporated by most people. Consuming it can protect against type 2 diabetes and heart problems (18).
Kale is also rich in potassium, which helps maintain electrical gradients in cells. Its adequate intake reduces blood pressure and the risk of heart disease (19).
And one advantage that cabbage has over other leafy vegetables such as spinach is that it is low in oxalates, substances found in some vegetables that can prevent the absorption of certain minerals (20).
Bottom Line: Many important minerals, such as calcium, potassium, and magnesium, are found in kale. Some of them are generally deficient in the modern diet.
9. It is rich in lutein and zeaxanthin, powerful nutrients that protect the eyes.
There are several nutrients that can prevent vision deterioration that occurs with age. Two of the main ones are lutein and zeaxanthin, carotenoid antioxidants found in large amounts in kale and other foods.
Many studies have shown that people who consume sufficient amounts of these two nutrients have a much lower risk of macular degeneration and cataracts (21).
Bottom Line: Kale is high in lutein and zeaxanthin, nutrients that are associated with a dramatically lower risk of cataracts and macular degeneration.
10. It can help you lose weight
Kale is very low in calories but contributes to a feeling of fullness. It has a very low energy density, and several studies have shown that consuming foods with low energy density can contribute to weight loss (22).
Despite its few calories, it contains small amounts of protein and fiber, two of the most important nutrients when losing weight.
And although there are no studies that have directly tested the effects of kale on weight loss, it makes sense that it is a good addition to any diet to lose weight.
To keep in mind
Fortunately, adding kale to your diet is easy. It can be added to salads and used in various recipes. Its leaves can also be made into snacks by sprinkling them with extra virgin olive oil and salt, and baking them until dry.
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