Evidence: High Possible Benefits: Very High Safety: Very High
TABLE OF CONTENTS
What is kale powder?
Brassica oleracea, also known as kale or leaf cabbage, is a popular vegetable sometimes sold in a powdered or capsulated form as a dietary supplement. Like most other vegetables, kale can reduce inflammation, boost antioxidant defenses, improve cholesterol levels, and more. This article is about the main benefits of kale powder, its potential side effects, the best time to take it, and more.
Possible benefits
All of the potential benefits mentioned below are dose-dependent. As with other vegetables, there is a sweet-spot dose that allows you to get most of the benefits without causing meaningful side effects or tolerance buildup in the body. We will discuss the best dosing protocol later in this article.
Major benefits
Improved blood flow and blood pressure – Kale contains high amounts of nitrate (approximately 138 mg per 100 grams). In the body, nitrate converts to nitric oxide, which is essential for improving blood flow and managing blood pressure. Kale powder can significantly reduce blood pressure in people with hypertension but it doesn’t cause your blood pressure to drop too low.
Improved exercise capacity – Because of its nitrate content, kale powder can notably improve both aerobic and anaerobic exercise capacity. This vegetable also notably reduces the oxygenation cost of exercise, which is most helpful for people doing hypoxic training.
Minor benefits
Antioxidant properties – This vegetable contains various antioxidants and can help reduce oxidative stress in the body.
Reduced inflammation – Like most other vegetables, kale powder can reduce chronic inflammation in most people.
Improved immune health – This benefit is secondary to the vegetable’s antioxidant and anti-inflammatory properties. Some people, especially those with autoimmune conditions, may experience a temporary worsening of their immune health after they eat or take this vegetable. That is generally nothing to worry about as it’s often just a sign of a hormetic response that helps adapt your body to the vegetable and other stressors.
Lowered blood glucose – While more studies are needed to confirm this benefit, kale powder seems to improve blood sugar levels in some people, especially those with insulin resistance or diabetes.
High micronutrient content – The vegetable contains very high amounts of vitamins and minerals (such as betaine, vitamin C, and potassium) per calorie. Some of these vitamins and minerals do not get absorbed very well when they come from vegetables because vegetables also contain a variety of antinutrients, such as oxalic acid. That is mainly a problem with zinc and iron but electrolytes and most vitamins should get absorbed just as fine as when they come from other foods. Unfortunately, if you take an extract instead of a whole vegetable, many of these micronutrients will get lost during extraction.
Improved cholesterol levels – Like many other vegetables, kale was shown in multiple studies to improve cholesterol levels by reducing LDL and increasing HDL cholesterol levels in the body. This benefit seems most notable in people with unhealthy cholesterol levels.
Lowered triglycerides – Supplementation may be somewhat beneficial, especially for people with high triglycerides.
Increased healthspan and lifespan – While the relationship between kale powder and healthspan or longevity hasn’t been studied directly, this vegetable has many mechanisms through which it might slow down aging and protect your body from various diseases.
Possible side effects
The side effects below are dose-dependent. The risk for them increases (often linearly but sometimes exponentially) as you increase the dose. Some of the side effects only apply to very high doses.
Initial adverse reaction – When you start taking kale powder or eating kale, things can get worse before they get better. This vegetable can temporarily worsen some aspects of your health and even make you sick after taking or eating it. That can be unpleasant, but it is usually a sign that the supplement is working and creating a hormetic response that allows the body to adapt and become more resilient in the long term. People with an autoimmune condition should be careful as the initial adverse reaction may be intense. If you have an autoimmune disease, start with a small dose or amount and gradually build your way up.
Allergic reaction – Some people are allergic to this vegetable and may experience an allergic reaction after they start taking it. Unlike the “initial adverse reaction,” allergic reactions typically don’t disappear until one stops taking or eating the vegetable.
Diarrhea – You can usually prevent diarrhea or stomach discomfort by taking this vegetable with a meal. Taking kale powder with food is better regardless because many of the bioactive compounds in the vegetable are fat-soluble.
Toxicity – Some bioactive compounds in kale have adaptogenic properties and act as mild stressors on the body. That is usually a great thing as it allows your body to adapt to specific forms of stress and become more resilient. However, stressing the body too much can be counter-productive and cause multiple side effects, including toxicity. While acute toxicity is extremely rare, taking or eating high amounts of this vegetable could lead to chronic toxicity and cause health problems over time. To prevent chronic toxicity or the buildup of tolerance, staying below 200 grams of a fresh vegetable or 20 grams of kale powder in a day is best unless you have a great reason to take more.
Contamination – If growing or storing conditions are not adequately controlled, kale can be contaminated with bacteria, molds, and other potentially harmful microorganisms. Many growers also use pesticides that can be unsafe. Choose the brand you get vegetables and vegetable supplements from wisely. For vegetable supplements, it is often best to use websites like Amazon, where thousands of users have reviewed and rated the products. You are less likely to buy something of lower quality there.
Who should not take kale powder?
You should probably avoid kale and kale powder if you:
are allergic to this vegetable
are predisposed to kidney stones
experience a severe adverse reaction after taking or eating the vegetable (though a mild adverse reaction is usually a great thing as it is a sign that the adaptogenic molecules in the vegetable are working and causing a hormetic response that allows the body to adapt and become more resilient)
have an autoimmune condition that makes your immune system overreact to xenohormetic stressors (you can eat or take this vegetable in that case, but it’s best to start with low amounts)
Who will benefit the most?
You should consider taking the vegetable or adding it to your diet if you:
have high blood pressure caused by poor blood flow
wish to optimize exercise performance
are deficient in vitamin C, potassium, or other micronutrients the vegetable is rich in
wish to improve general health
have a high budget for supplements and are willing to experiment with a variety of them (assuming you don’t fall into any of the categories that should avoid this vegetable, kale powder appears safe and is unlikely to do more harm than good for most people)
How much kale powder should you take?
If you are deficient in potassium, vitamin C, or any other nutrient this vegetable provides high amounts of, the best dose is a dose that helps you cover the deficiency. Fixing a nutrient deficiency should be your primary concern in this case.
Because kale contains adaptogenic compounds, it acts as a mild hormetic stressor on the body, which allows your body to adapt and become more resilient to certain kinds of stressors in the long term. A higher dose of these adaptogens isn’t necessarily better because they may stress out the system too much.
The sweet-spot dose typically ranges anywhere between 100-200 grams of fresh vegetable or 10-20 grams of dry kale powder daily.
If you buy an x:1 extract, divide the dry powder dosage by x. If you purchase an extract standardized for nitrates, the sweet spot dose of nitrates is about 400-500 mg.
The higher end of this range usually provides slightly more benefits in the short term. If you plan to take or eat this vegetable regularly for a longer time (multiple months or years), the lower end is probably a better way to go.
You would develop tolerance to the xenohormetic molecules faster if you took or ate higher amounts. Additionally, very high doses can put too much pressure on your system and cause health problems if you take the supplement for a prolonged period.
While this vegetable could theoretically cause acute toxicity, you’d need to take an extremely high amount that would be way beyond what even the most potent supplements contain.
Like most other plants, it is best to cycle kale powder and take about two days off weekly to reset your tolerance to the adaptogenic and xenohormetic compounds in it. That will allow you to keep getting the benefits in the long term.
Best time to take kale powder
To maximize exercise performance, take kale powder or other sources of nitrate 1-2 hours before an exercise session.
Whether you take this vegetable in the morning or the evening does not make much difference. Both options are fine so feel free to experiment.
Some of the main bioactive compounds in this vegetable are fat-soluble, so you want to take it with food or a dietary source of fat.
Interactions
Cocoa Cocoa helps maintain high nitric oxide levels after they’ve been increased by exogenous nitrate intake from kale.
Garlic Garlic enhances the signaling of nitric oxide.
D3K2 Vitamin D and vitamin K help transport calcium through the body. When you are deficient in these two vitamins, calcium may bind to oxalic acid from kale and form calcium oxalate kidney stones.
Vitamin C As an antioxidant, vitamin C reduces the oxidation of nitric oxide, keeping your nitric oxide levels elevated.
Calcium Calcium should not be taken with a source of oxalic acid like kale powder. This combination may lead to calcium oxalate kidney stones.
Where to buy kale powder supplements?
In most countries, Amazon is the best option for ordering kale powder and other vegetable supplements. They offer some very affordable products backed by many positive reviews. Also, you can choose from a wide range of brands without having to search through other markets on the Internet.
Some brands display the dosage per serving instead of per pill or capsule. Therefore, you may accidentally buy something less potent than you intended. Do not fall for this marketing trick.
FAQ
As with most other vegetables and vegetable supplements, it is best to cycle kale and take a break from it for about two days per week to reset your tolerance back to baseline. That will keep your body sensitive to the vegetable and allow you to keep getting the benefits in the long term.
Eating a fresh vegetable is almost always better as it contains many micronutrients and other beneficial compounds that get lost during extraction. On the other hand, supplements and dry powders don’t go bad nearly as fast as fresh vegetables, don’t need to be stored in perfect conditions, and are often cheaper.
This vegetable by itself should not worsen your sleep quality in any way. However, it’s best to take it with food, and you generally don’t want to eat any food right before bed as it could worsen your digestion and sleep quality.
Dry kale powders and supplements can expire but not nearly as fast as fresh vegetables. They can also lose potency over time but very slowly if you store them well. Keep the supplement in a cold, dark, and dry place. It should remain just as potent for many months or even years there.
Yes. Kale contains adaptogenic and xenohormetic compounds that act as mild stressors on the body. That is usually a great thing as it allows your body to adapt to specific forms of stress and become more resilient. However, stressing the body too much can be counter-productive and cause multiple side effects, including toxicity. While acute toxicity is extremely rare, taking or eating very high amounts of this vegetable could lead to chronic toxicity and cause health problems over time. High doses can also make you develop tolerance much faster than lower doses, and they may be less effective at improving health in the long term.
While you could safely take higher doses, there is usually no point in eating more than 200 grams of a fresh vegetable or 20 grams of dry kale powder daily. This amount should give you most of the benefits without meaningful side effects. The only exception is if this vegetable is helping you fix a nutrient deficiency, in which case you may want to take more of it.
Unfortunately, there is not much information about the half-life of kale in the body. However, most of the effects of this vegetable are cumulative, so they mostly happen in the long term rather than acutely. Therefore, the half-life of this vegetable isn’t very relevant in practice.
Eating this vegetable would break a fast and reduce some benefits of it. Taking kale powder would probably have little to no effect on fasting.
References
Most of the information in this guide is based on scientific research that can be found and verified in the PubMed medical library. We highly encourage you to use the library to verify anything you read in this article. We excluded from consideration studies that are either confounded or have a high conflict of interest.
