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Green powders are supplements that are intended to give you essential nutrients you need from vegetables.
This article explores whether green powders such as athletic greens are a good replacement for vegetables and where they fall short.
I’m not going to go into which diet is best for health and longevity here but whatever diet you prefer, everyone can agree that vegetables play an important role in health. The Dietary Guidelines for Americans 2010 recommends making one half of your plate fruits and vegetables and The World Health Organization (WHO) recommends an intake of five to eight portions (400-600 g) daily. This has been linked to reduction in a wide range of age-related diseases from cardiovascular disease to cancer.
The main vitamins found in vegetables are vitamin A, C, E and folate. Vitamins C and E are important antioxidants, they reduce the formation of harmful compounds such as nitrosamines inside our cells and protect our cell membranes from damage. Folate helps protect our DNA from damage. Inadequate intake can lead to reduction in DNA methylation at certain points which can impair normal controls on the expression of genes. Adequate daily intake of these vitamins can be achieved with a diet rich in vegetables. Exceptions are the need for supplementation of some vitamins and folate in pregnant women.
Minerals we need such as potassium, magnesium, manganese, selenium, calcium, and copper can all be met with adequate vegetable intake. Calcium supplementation may be needed in older individuals. Many of these minerals are cofactors which help important enzymes that protect against oxidative tissue damage.
Phytochemicals are chemical compounds produced by plants that play an important role in promoting health by interfering with cellular functions, gene expression and cellular metabolism in different ways. Vitamins and minerals can be considered phytochemicals but the name encombasses a wide range of other compounds that have individual and additive (synergistic) effects. These include things like sulfides, carotenoids, flavonoids such as quercetin, phenols and others like resveratrol.
Fiber refers to a group of carbohydrates that we cannot digest because we lack the necessary digestive enzymes to break them down. This does not mean fiber doesn’t have health benefits. To the contrary, increased fiber intake has been linked to a significant decrease in average mortality. Fiber reduces cholesterol levels by increasing the rate of excretion in bile, lowers blood pressure, slows absorption of glucose to prevent spikes, reduces contact time between potential carcinogens and cells of the digestive tract by increasing fecal bulking and viscosity and many other effects.
Fermentable fibers are fibers that are digested but certain types of gut bacteria and are especially good for gut and general health. These include fibers such as pectins, beta-glucans, guar gum, inulin and oligofructose. A good source of fermentable fibers is beans and legumes. In one study, 30 grams daily of fermentable fibers was shown to improve kidney function in people with kidney disease and reduce their levels of inflammation.
It seems that many of the beneficial effects of vegetables are linked to the fiber content.
While green powders can contain some of the healthy ingredients listed above, they may not contain optimal doses. We don’t know if the dose of their ingredients are actually that beneficial.
The main issue I have with green powders is the lack of fiber. Fiber intake is a main reason why vegetables are healthy in the first place. Removing fiber means losing these benefits. Athletic Greens for example domains only 2 grams of fiber per serving while the recommended daily fiber intake should be close to 30 grams.
Green powders can be a healthy supplement to an existing healthy diet but is not an alternative to including vegetables in our diet.
