Humans can't digest wheatgrass

WinonaWinona Raw Newbie

The argument is, cows ferment grass for days in order to digest it. How can humans absorb nutrients from wheatgrass without fermenting in our stomach? Let’s use SCIENCE here, folks. I have to prove the benefits of wheatgrass to my skeptical boyfriend! I’m willing to accept that wheatgrass is unhealthy, but prove that too.

This blog Skeptico asserts that humans can’t digest wheatgrass. His sources include the following:

Here’s the explanation of why, from New Scientist Without their cargoes of microbes they would be unable to make use of it at all. In addition, unless microbes break down the plant cell walls, the herbivore’s own digestive enzymes would have difficulty gaining access to the cell’s contents. The reason that herbivores generally have complex digestive tracts is to slow the passage of food, and so prolong contact with the microbes that help to digest it. The digestion of cellulose is an anaerobic process, of the kind commonly known as fermentation. All parts of the gut absorb the volatile fatty acids produced in the process and these provide the herbivore with energy. ...

Secondly, animals with large bodies can also have large guts, and so can contain large amounts of material that is fermenting slowly. Large herbivores generally retain their food in their guts for longer than smaller animals, and this maximises the opportunity for the breakdown of cellulose. Small herbivores generally depend for their energy more upon the contents of a cell than its walls, and so they must select plant material of higher quality.

From Anatomy and Physiology of Animals/The Gut and Digestion: Ruminants swallow the grass they graze almost without chewing and it passes down the oesophagus to the rumen and reticulum. Here liquid is added and the muscular walls churn the food. These chambers provide the main fermentation vat of the ruminant stomach. Here bacteria and single-celled animals start to act on the cellulose plant cell walls. These organisms break down the cellulose to smaller molecules that are absorbed to provide the cow or sheep with energy. In the process, the gases methane and carbon dioxide are produced. These cause the “burps” you may hear cows and sheep making. Not only do the micro-organisms break down the cellulose but they also produce the vitamins E, B and K for use by the animal. Their digested bodies provide the ruminant with the majority of its protein requirements.


  • WinonaWinona Raw Newbie

    Here’s what Skeptico writes: 1. Wheatgrass is a low quality food that does not contain anything even remotely close to “all of the vitamins and most of the minerals we need”. (See wheatgrass nutrition data: 7% daily values (DV) of Vitamin C; 10 iron; zero percent of everything else. Zero! Sheesh – eat an orange.) 2. Wheatgrass does not contain enzymes that aid human digestion. Any enzymes that wheatgrass contains are enzymes that help wheatgrass metabolize its food; wheatgrass enzymes do not help you digest wheatgrass or anything else. (They may both be called “enzymes”, but they are different molecules.)

  • WinonaWinona Raw Newbie

    3. Special microbes and enzymes are necessary in the gut to break down the cellulose in grass. Humans do not have these enzymes, and so humans can’t digest grass, whether it is juiced first or not. 4. The digestion process, even in ruminants, is necessarily slow. This means that (a) human digestion would not be slow enough to digest wheatgrass (even if human guts had the necessary microbes, which they don’t), and (b) if it was that slow (and had the microbes), wheatgrass would still not be absorbed into the body “within 20 minutes” as is claimed. 5. Likewise, claims of a “high” after drinking wheatgrass are due either to the power of suggestion or some physiological reaction due to the body not being able to digest what it was just fed. 6. Because it cannot be digested, wheatgrass cannot possibly be an energizer, build your blood (whatever that means), cleanse your body, or do any of the other magical things claimed for it.

  • elizabethhelizabethh Raw Newbie

    hence the reason people juice wheatgrass (because we cannot break down the cell walls).

  • WinonaWinona Raw Newbie

    But his argument is Special microbes and enzymes are necessary in the gut to break down the cellulose in grass. Humans do not have these enzymes, and so humans can’t digest grass, whether it is juiced first or not.

  • chicorychicory Raw Newbie

    isn’t cellulose the inside wall of the plant (ie. the roughage?) that’s the part used to make paper, etc. If wheat grass is indeed taken in juice form, isn’t the cellulose (undigestible roughage) left behind in the pulp? that’s what makes me think this is the part left out when we juice

    Some animals, particularly ruminants and termites, can digest cellulose with the help of symbiotic micro-organisms that live in their guts. Cellulose is not digestible by humans and is often referred to as 'dietary fiber' or 'roughage', acting as a hydrophilic bulking agent for feces
  • Annabelle77Annabelle77 Raw Newbie

    My undergrad degree is in Anthropology, and I focused a lot on human origins… Before 2.6 million years ago, climate change forced the hominid population into different dietary niches. Two species resulted: one that ate higher quality, easy to digest foods (Paranthropus boisei), and one that ate lower quality foods (Paranthropus robustus). (2.6 to 1.2 MYA)

    P. Robustus evoled “megadontia” or huge teeth to masticate dense, fibrous, lower nutrient vegetation. They had LARGE digestion systems to deal with their diet. They also had smaller brains since most of their energy was relegated to the Gastrointestinal tract.

    P. boisei, on the other hand, evolved smaller teeth, and a significantly smaller GI system because they were eating higher quality, higher nutrient, and easier to digest foods. Their bodies spent MUCH less energy on digestion, and more energy was relegated to the brain. Due to higher reproductive success over time, larger brains evolved with a large amount of energy relegated to the brain and its development.

    The point of this is that P. robustus went extinct, and P. boisei is an ancestor of ours. Out bodies are designed to eat nutrient-dense, enzyme-rich foods like fruit, seeds, nuts etc. I can’t imagine that any of our ancestors would have eaten grass if better food was available.

    There may be some benefits to eating grasses or other “tough” vegetation, but I personally dont think that we are designed to eat them…

  • angie207angie207 Raw Master

    We don’t currently have access to foods that are anywhere as nutritious as they used to be, because of depleted soils, etc. We may not have been designed to eat grass, but juicing extracts the nutrition from the cell walls and makes it available to our bodies. Ann Wigmore (in The Wheatgrass Book) said that we can’t break down the cell walls of the wheatgrass like cows can, and that is why we juice it. She also said that, according to a doctor she consulted, wheatgrass theoretically has everything needed to sustain life for weeks or even months at a time.

  • angie207angie207 Raw Master

    “The Wheatgrass Book” tells about some of the scientific research Ann Wigmore did or had others do for her.

  • Annabelle77Annabelle77 Raw Newbie

    True, chlorophyll is pretty amazing stuff… and I would imagine that juicing takes care of the breakdown of fiber… since you barely get any fiber when you drink the juice.

  • WinonaWinona Raw Newbie

    Chlorophyll is a very beneficial part of all green plants. When skeptico says that wheatgrass has no nutrients, first of all: he’s only looking at vitamins, not minerals. Second: he’s looking at an analysis of conventional, NOT organic wheatgrass. big difference!

  • angie207angie207 Raw Master

    Interesting – we can skew “scientific results” to show all kinds of things now, can’t we?

  • Yes-Skewed indeed! I know there are people arguing both sides of this issue, but honestly, I think your experience will tell you what to do. As many of you David Wolfe enthusiasts will know, “grasses” are the only type of plants yet discovered that can potentialy hold all known trace minerals, if they’re grown in a medium that is very mineral rich. When you juice that grass, you then get really an organic mineral supplement right into your system. A fantastic food! So-we use modern technology (juicing) with ancient wisdom! Awesome! :-)

  • chicorychicory Raw Newbie

    what i don’t get is, why do people pay 15.00 for frozen wheatgrass when they can grow their own so cheaply in just a few days? Plus you can control how it gets its nutrients

  • elizabethhelizabethh Raw Newbie

    the whole point of juicing is to remove the cellulose so that we can access what’s inside the plant cells, without having to digest them.

  • Wheat grass or any other form of grain or grain grass is not good for people. Most people’s systems will handle it for a while, or get used to it, but it will wear down a person’s health eventually. It may have tons of nutrients, but since the human digestion is not able to assimilate it well, much of the nutrients are lost, and the system is taxed in the digestion process. I feel like this is one of the main problems with the Halelluja diet. Also carrots can be hard for some to digest. It is best to stick with nutrient sources that the body can digest well.

  • angie207angie207 Raw Master

    pulse – I understand that eating the whole grass would be taxing on the system because it’s too hard for our bodies to break it down, but why do you say that grain & grain grasses (juiced) will wear down a person’s system?

  • I am not a 80/10/10 raw vegan, but I do agree with the ideas of the natural hygenests. Just as the research that Winona found suggested, grains are hard for a human to digest. If a food is hard to digest then the digestive system is over burdened and pulls vital energy from other systems which can wear down the whole body. Our bodies are amazing, but they were never intended to run well on grass or grass seads. Grain is a grass. Corn, Barley, Wheat, ect. Look at the leaves. They are not a herb, they are a grass. Our digestive juices cannot handle this type of food. The best way it can be eaten is toasted, just like the best way to eat meat is cooked, so neither should have a place in a raw food diet.

  • ZanzibarrrZanzibarrr Raw Newbie

    Well Annabell nobody knows that, whether afarensis goes into Homo, or africanus goes into robustus and boisei, or afarensis goes into africanus and goes into Homo, or Hadar goes into africanus and then Homo etc etc… ALthough I like Yves Coppens a lot, being a frenchy, you have to believe in evolution etc… Better food than grass? Greens are packed with enzymes, proteins, nutrients… juicing taking care of the fiber? alas…and putting so much load on your adrenals and pancreas.

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