Doing Greens Right: Nutrients and Anti-nutrients

Leafy greens are an important part of the natural human diet when it comes to minerals and protein. But not all greens are alike! Not all greens are meant for human consumption! In fact, some greens contain a high load of anti-nutrients and compounds that are intended to repel animals. why we need to know what we are doing not to mess this up!

For quick readers:

Green food, especially tender leafy greens, play a substantial role in the natural human diet as a source of minerals and proteins. However, not all greens we eat today are equally beneficial for our species, and some should even be limited as they contain high levels of anti-nutrients or are too hard to digest. The combination of eating young and tender lettuces, sprouts, and microgreens as “staple greens” and tropical fruit tree leaf extracts and mineral-rich seaweeds as a functional food offers the benefits of getting both, fresh greens and our “evolutionary greens.” On the other hand, greens that are high in anti-nutrients are not naturally part of the human diet and should be avoided, especially in smoothies.

In this article, we will elaborate on what types of green foods we have adapted to eat and what types of green functional foods and herbs are a powerful add to our everyday greens!

The Good: Nutrients in greens

Leafy greens are rich in a variety of minerals, proteins, and secondary plant metabolites.

The amount of minerals found in plants highly depends on the mineral content of the soil. Plants themselves can also suffer from mineral deficiencies! the content also varies between the different types of green foods and how they were grown. Besides nutrient content alone, it also matters how bioavailable the nutrients are and the amount we can consume of a particular food: For example, we can consume much more tender leafy greens than herbs. Or we can consume much more fruit than greens.

What minerals are in greens?

Greens contain all minerals that we need: magnesium, potassium, iron, phosphorus, calcium, sulfur, boron, copper, zinc, selenium, manganese, boron, molybdenum, and iodine in seaweeds from marine environments.

• Iron
• Calcium
• Potassium
• Sulphur
• Phosphorus
• Molybdenum
• Manganese
• Selenium
• Boron
• Copper
• Zinc

Seaweeds: marine greens provide special nutrients

Seaweeds are leafy plants from the sea. They have a different nutrient composition than greens that grow on land. Iodine and calcium are key nutrients in seaweed that are important for human health. Iodine deficiency can be a cause of concern when not living close to the iodine-rich sea. Sea moss or kelp are two examples of how to get iodine into the diet. If you do not live in a marine environment, iodine-rich seaweeds, like sea moss or kelp, should be added to the diet.

Minerals from greens or fruits?

Many nutrients found in greens are also found in fruits – just not as dense. Because fruits have a higher water content, the nutrient quantity per weight is often lower in fruits than in greens, but fruits can be consumed in much larger quantities than greens! Thus, not solely the absolute nutrient content matters – but also how much we can consume of a food type. And how bioavailable the nutrients are within the food matrix (i.e., anti-nutrient content), and if it’s our species’ natural food source.

For example, iron: While greens are rich in iron, fruits are too and provide a substantial amount in the quantity we have evolved to eat. However, access to ripe tropical fruits is crucial in getting the necessary nutrients!

Eating the power of photosynthesis: minerals and protein

To better understand green foods and leaves as nutrient sources, we can ask: What are the functions of green parts in the plant itself? What minerals does the plant need for its own biochemical functions? The process of photosynthesis requires many types of enzymes (proteins) and the power of minerals as redox agents and cofactors, which is why they are present in abundance in green foods.

The green parts of plants are the photosynthetic and vegetative parts. It’s where plants produce energy. Green cells contain chlorophyll in chloroplasts where glucose as an energy carrier is produced but not stored (sugar is transported to starchy parts and fruits) and are especially rich in various minerals, amino acids (protein), as well as a variety of polyphenols, and essential oils that serve different functions like defense or attraction.

Why are greens, in particular, a main source of magnesium and iron? Because those two are two main minerals involved in photosynthesis:

The chlorophyll-rich chloroplasts are the organelles that give green plant parts their color and contain most of the iron and magnesium:

“Chloroplasts represent the iron-richest organelle in plant cells containing 80–90% of the iron found in leaf cells” López-Millán, 2016

Image of a lettuce leaf under a microscope. Chloroplasts (specialized vacuoles in green cells) are the plant cell structure with the most iron because the mineral is needed for the production of chlorophyll and photosynthesis.

The chlorophyll molecule itself contains magnesium, which is why green foods are magnesium-rich. Chlorophyll has been shown to have important beneficial effects on human health.

The bad: High levels of anti-nutrients in greens

Leafy greens can contain a substantial amount of anti-nutrients and harsh secondary metabolites, which is why not all are equally suitable for humans.

Some of the unfriendly compounds from grains, legumes, and nuts are also found in leafy greens, which impede the digestion and bioavailability of nutrients.

Tender, young, and succulent leaves generally contain less anti-nutrients! But generally, the vegetative parts of plants protect themselves from unfriendly chemicals towards whoever wants to eat them. Some greens – especially the dark, bitter, or otherwise unpalatable types, have high levels of anti-nutrients, like the so-called “superfood” kale.

Self-defense chemicals found in greens:

• Oxalate
• Phytates
• Nitrates
• Tannins, which can be very bitter
• Lectins impede the digestive system
• Trypsin inhibitors, impede protein digestion
• Saponins are bitter and impede lipid absorption
• Alkaloids, of which many are toxic to animals

Toxins and anti-nutrients in plants are the results of an evolutionary rat race (except for fruits). Animals, on the other side of the coin, evolve resistance towards the protective compounds of their food source. Fascinatingly, some of those powerful compounds are a double-edged sword, as many compounds help combat parasites and act as antimicrobial agents! We can see that plant compounds are a balance between harmful and helpful.

This is also where instinct-driven self-medication of animals comes into play. The urge of animals (including chimpanzees) to feed on strong-tasting herbs can help combat infections and pain. But for nutrition purposes, animals avoid bitter taste! The notion that “bitter is healthy” is not backed up by patterns observed in nature! And while self-medication is a natural thing, we should not go against our own taste-bud instincts! Bitter signals “stay away” in nature, an adaptation that protects us from ingesting too many plant toxins!

Eating the right greens

What does this all mean for humans? Are greens a healthy source of nutrients? And what types of greens?

To understand what types of greens are the ones most suitable for our species, we can listen to our own instincts but also learn from our past and our we can study our closest living relatives, the chimpanzees. Leaves play an important role in the diet of apes and other primates generally. Some primates are even folivores (leaf-eaters), not frugivores. Chimpanzees are frugivores, but they consume a substantial amount of young tender leaves from trees. They go for the succulent sweetish greens, which provide a great amount of bioavailable minerals and protein:

Chimpanzees prefer leaves with high ash (minerals and nutrients) protein instead of cellulose and tannins. Tannins were off-putting as a rule number one! They have preferences in picking their greens that follow the basic rule of maximizing nutrients while minimizing anti-nutrients: “Chimpanzees preferred leaves containing higher protein content, but did not consume leaves containing high condensed tannin regardless of protein content.” (Takemoto, 2003)

Like chimps, humans naturally tend to prefer greens with low anti-nutrient levels: tender lettuce and young greens like microgreens and sprouts with a sweet-sour dressing (imitating a fruity taste):

In our species’ diet, tender, young leaves, like succulent lettuce, young leaves, microgreens, and sprouts, should make up a substantial part (as it is in the chimpanzee diet). Additionally, mineral-rich supplements from greens like powdered tree leaves and seaweeds could be an interesting nutritional and herbal addition. Greens that are high in anti-nutrients or tannins or do not taste good on their own, are not really part of the natural human diet and should be limited, especially in smoothies.

Chimpanzees also go for seaweeds, barks and herbs at times, to supplement their diet. Thus integrating mineral-rich green powders and seaweeds is a good idea, especially if we do not tend to eat greens in bulk. Read our in-depth article on this topic here.

• Sprouts
• Young leaves of lettuce
• Microgreens
• Iceberg lettuce
• Butterhead lettuce
• Romain lettuce
• Gras juice powders
• Moringa
• Other tropical tree leaves extracts and teas
• Seaweeds
• Green veggie fruits like cucumbers and zucchini

How much greens should we get?

The answer is, it depends! It depends on what other types of food we eat. If we look into nature, chimpanzees eat a large amount of young leaves from trees, but if they can, they go after ripe fruits (fruit availability varies). Fruits also contain all the minerals that greens do, but in lower concentrations, as fruits also provide a lot of liquid. Tropical fruits, wild fruits, contain much more nutrients and minerals than modern, cultivated ones, which is why we should consider natural supplements, like functional foods.

In our species’ diet, tender, young leaves, like succulent lettuce, young leaves, microgreens, and sprouts, should make up a substantial part. Additionally, mineral-rich supplements from greens like powdered tree leaves and seaweeds could be an interesting nutritional and herbal addition. Greens that are high in anti-nutrients or tannins or do not taste good on their own, are not really part of the natural human diet and should be limited, especially in smoothies.

Green powders like moringa leaves, tropical fruit tree leaf powders, seaweeds, and powdered wild fruits seem reasonable and very helpful to up our mineral intake, while trying to imitate our natural food patterns without easy access to the foods that we need.

Here are three ways to increase our greens in a healthy way:

1. Juicing greens

Juicing tender greens with fruits helps us eat more greens. Greens and fruits are a natural combination, which might be the reason we love the taste!

2. Combining greens and fruits in salads

Fruit-enriched salads based on leafy greens have become an integral part of plant-based diets for a reason:

Many types of lettuces without dressing or in combination with fruits do not appeal to human visual or olfactory instincts or taste buds. This innate knowledge is important in the natural human diet.

The combination with fruits also helps the absorption of some nutrients. For example, vitamin C and fructose increases iron absorption.

3. Taking the right green supplements

Due to the limited access to our evolutionary green food sources, we might consider herbal extracts from tropical greens to get additional benefits from greens, like the powerful antiparasitic, antioxidant, and polyphenolic components that we have evolved to consume! We can use tropical herbs as functional foods and reap the health benefits of their unique bioactive molecules and nutrients.

• The most famous example is moringa green powder.
• Some nutritional supplements are made from tropical leaf extract: Guava leaf extract for zinc or curry leaf extract for iron are available.
• Other supplements to consider are algae: Green algae, red calcium algae, sea moss, kelp with iodine, etc. As with all supplements, quality is key.
• Teas are also an easy-to-find addition, like guava leaf tea, papaya leaf tea, or mango leaf tea, which are known for their benefits to people living in the tropics.

Read more about greens in the natural human diet here.

If you like to read more on species-specific foods in the human diet, visit our food group overview.

References

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