What is a greens supplement?
As the name implies, greens supplements are plant-based products that are dried and made into powders, tablets or capsules. Common ingredients include wheat grass, alfalfa, spirulina and vegetables. The supplements sometimes include fruit, probiotics, or extra vitamins and minerals. These products are touted as a convenient way to increase the number of vegetables in a person’s diet. Additionally, added ingredients may provide health benefits beyond those achieved by solely eating more vegetables. Most products also contain a small amount of healthy fat, fiber, and protein in similar ratios to those found in the foods that make them up.
In my article on multivitamins, there is a pretty detailed description about the difference between multivitamins and greens supplements. But briefly, a traditional multivitamin contains chemically synthesized isolates (i.e. the vitamin C in a multivitamin is ascorbic acid), whereas a greens supplements are a concentrated form of whole food (i.e. a supplement containing kale or broccoli will have vitamin c in its “natural form” as it exists in the plant itself). There is little doubt that the best way to get nutrients is through whole foods rather than supplements, and supporters of greens supplements argue that taking them is essentially the same as eating the constituent foods.
Diets rich in fruits and vegetables are repeatedly shown to be associated with a lower risk of heart disease, obesity, cancer, diabetes, high blood pressure and a host of other health woes. Most people know that. A considerably smaller number of people, however, actually eat diets rich in fruits and vegetables. Greens supplements are the next best thing. And while no supplement can replace a produce-rich diet, greens powders are a convenient, relatively inexpensive way to make a less-than-ideal-diet healthier.
Companies that produce greens supplements make claims about the health benefits of certain ingredients that are not supported by any real evidence.1 For example, spirulina is touted as a great source of protein and vitamins. And while it does contain complete protein and an array of vitamins, it is very expensive and those nutrients can easily be obtained from other, cheaper sources. Wheatgrass is a common greens supplement ingredient and its proponents believe it can prevent cancer. The American Cancer Society, however, believes that it cannot, at least “based on the current evidence.”2
The evidence of decreased disease in high-produce diets is based on total fruit and vegetable intake and not so much on very high intakes of a particular fruits and vegetables, though certainly some are healthier than others.
As with any supplement, there is a risk of contaminants and toxins within the products. Given the lack of regulation of dietary supplements, you can never be completely certain that what is on the label is what is in the product. Certain vitamins can be dangerous at high levels, and it is possible that consuming large amounts of these products can put a person at risk for toxicity. Certain additions, such as licorice, can interact with medications as well.3 All of these risks can be minimized by buying from a reputable company, using an organic product, taking only the recommended dose, and going over the particular formulation with a knowledgeable health care provider.
Greens supplements come in many forms, and most capsule and tablet forms require taking multiple pills multiple times per day. That kind of schedule is going to be very difficult to follow, and for this reason I do not recommend greens pills.
Powders can be taken once per day, so are much more convenient. And since different products have different ingredients, it makes sense to use more than one and alternate them. This approximates eating different types and fruits and vegetables each day. Two of my favorite products are Athletic Greens and Garden of Life Super Green.4 These can be mixed with water or added into a shake.
Once again, a supplement cannot take the place of a healthy diet. However, a good greens powder can certainly make anyone’s diet healthier.