Ben B wrote:
My concern is that veganism is not suitable for everyone because it rely on conversion from simple forms to more complicated one, and not all people is genetically apt to do this.
So, vegans may be short on the following nutrition requierments, if their body can convert precursors :
* Vitamin A from betacarotene (source)
All humans are pretty bad at absorbing beta-carotene. On our best day, we can only absorb about half of the beta-carotenes we eat. Sometimes it can be as little as 10%. Beta-carotene conversion into retinol is actually highly dependent on one's blood levels of vitamin A. Someone like myself who eats tons of beta-carotene rich foods will have a much lower conversion rate into retinol than someone who is retinol deficient. In other words, your body tightly regulates the amount of beta-carotene absorbed based on how much you need. However, if I ate retinol rich foods like liver and eggs, my body would be FORCED to absorbed the retinol even though I don't need it. Our digestive tracts our not set-up to regulate retinol since our fruit-eating ancestors didn't eat much of it. Even more interestingly, animals who we know are meat-eaters have enzymes that break down retinol if they get too much. If an animal has this ability it's actually one of the indicators that they are a meat-eater. If they don't have this ability, it almost always means they are herbivoires. Guess what? We don't have that enzyme!
The study you posted may show that some people are much better at converting beta carotene into retinol, it in no way shows that they have someway adapted to animal nutrition. I think it is important to realize that whether or not we have the particular gene that makes us better than average at making the conversion, it is virtually impossible to become vitamin A deficient by eating a fruit and vegetable based diet.
* Long chain omega-3 from short chain omega-3 (source)
The story is quite similar here. MANY factors come into play when we are talking about converting ALA into EPA and DHA. Your source covers one important one which is the omega-6 level. If you are eating too much omega-6 fats found in animal foods, oils, and nuts and seeds, you won't be able to convert much ALA into higher chain fats. Once that omega-6 level is dropped and a diet that is sufficient in ALA is undertaken, high chain omega 3s will rise to appropriate levels. Unfortunately your study only tests this theory for about 40 days. I wouldn't imagine that would cause very much difference in reversing a lifelong diet of high-omega 6s. Would you?
Some reasons why I think it's a better idea to lower our omega-6, rather than increase omega-3 intake:
If we look at our ancestral diets, we know for a fact that we had an omega-3:omega-6 ratio of about 1:1. What we fail to have pointed out to us, is that not only was this a 1:1 ratio, but the total amount of omega-3 and omega-6 consumed on a daily basis was only around 2 grams of each. How much do we consume now?
Our omega-3 fat content has remained around 1.5 - 2.0 grams per day, but our omega-6 intake has literally rocketed up to over 20 grams a day!
Even our recommended intakes for these fats makes no sense at all:
Notice, the recommendation is to have 1.6 grams of omega-3 and 17 grams of omega-6! This just doesn't make any sense whatsoever.
In addition, several other factors come into play such as total amount of fat, the source of the ALA, the amount of animal foods present alongside the ALA, the antioxidant status that protects the ALA as it is converted. So no one can say with certainty that they need to eat fish or grass-fed meats or eggs to get their long-chain fatty acids because they probably haven't even tried eating in the way that would lower their omega-6 levels. Moreover, when people choose to eat these animal foods, they often cook them which completely oxidizes the very volatile omega-3 fats in them.
And animals products is also an interesting source of vitamin D in winter, and of vit B12 (sun dried mushrooms are a good source of vit D2, but i'm not sure it is an effective source of vit D contrary to vit D3)
Our main source of vitamin D should be the sun. Originating from the tropics, humans would have been exposed to direct sunlight almost every day of the year allowing us to maintain optimal vitamin D levels. As humans moved away from the equator where cold dark winters drastically lowered our vitamin D levels, we needed to resort to animals to provide it for us it. Unfortunately we don't get nearly enough vitamin D from animals as we could from the sun. One egg might give you 50 units assuming you don't cook it of course. Going outside for a 15 minute walk will give you upwards of 10,000 units which is the amounts we actually need to be in optimal health. 200 egg omelette anyone?
B12 is a nutrient produced by bacteria, not animals. There are trillions of bacteria in our digestive tracts and even more in each breath of air we breathe. Many different types of these bacteria produces B12 that our bodies can use. I should say COULD use, if we had enough of the good bacteria in our GI tracts. There is a substance called intrinsic factor produced by the parietal cells in the stomach that is what ushers the B12 into our blood stream. If we have gut flora imbalance, intrinsic factor can't work. If we eat too many grains, intrinsic factor can't work. If we become stressed or overly acidic, intrinsic factor can't work. These things are independent of whether or not we eat steak or rabbit food. There are PLENTY of meat-eating people out there who are B12 deficient and just as many vegans who have levels that are perfectly fine.
Mark Harris wrote:
Certainly in the Uk the only people with vit D deficiencies are those with dark skins who cover up their skin with clothes excessively for religious reasons.
Brian Bales wrote:I'm currently building my food forest and garden/pasture system with the ideal of producing 95% of the food I need for myself and family. I live on 1.5 acres of land but the bulk of this project is taking up only about .5 of the 1.5 acres. Its been a tricky process but I am beginning to see results. I have planted most of the trees in my food forest and most of them are established (I lost several last year that I need to replace due to gophers). There is an established pecan tree on my land already but in addition to that I have planted almonds and pistachios. I'm working on planting bush fruits, herbs, beneficial and insectiary plants now as well as edible ground covers like strawberry, ground plum and purslane.
I've been doing a great deal of research on perennial vegetables and have found some great additions. I just got some cutting of tree kale/collards. I have high hopes for this plant. Supposedly 100 square feet will produce around 300lbs of food a year. I also have artichokes, asparagus and rhubarb planted. I am going to be trying seakale this spring too. The ground plum is an interesting legume that I hope will prove a useful ground cover and food plant. I also will be planting sorrel, nettle, good king henry and purslane to name a few.
As to cereals I am planting them too, some are going in a rotation system of animal paddocks and cereal beds others will be planted in the open spaces in my orchard. I have several cereal crops to test. Once I can evaluate their suitability to growing here. Then I will streamline my selections to just a few. I'm testing wheat (Sonora, spelt and kamut), millet, sorghum, flax, quinoa, amaranth, chia, barley, buckwheat, flint corn and a few other oddities like rocky mtn bee plant. Some like quinoa, amaranth and chia are especially important to me because of their high nutritional content and their use as both grains and green vegetables.
I am including animals in my projects. I currently keep nigerian dwarf dairy goats, pilgrim geese and guinea fowl. I intend to add chickens and turkeys to my collection. I also plan to have a couple bee hives. Eventually I plan to build a greenhouse and keep an aquaponic system where I can raise channel catfish and maybe tilapia or carp.
One of the biggest challenges has been working out a system where all the money I save on growing my own food doesn't go down my animals throats instead. A big part of that is keeping numbers minimal. I feed them conventional foods like alfalfa and grains but I am working away from that. One of the most important feed sources I've been looking into is tree crops. My animals love poplar trees and I have a lot of them growing on my property so I've had success supplementing some of their feed with poplar. I'm also planting polyculture hedges with the intention of using them as animal feed. I'm planting a mix of acacia, honey locust, rosa rugosa, black mulberry, sawtooth oak and a few other misc items like elderberry, wild plum and hazelnut. All things useful to me and to the animals. Never underestimate the usefullness of the edges
pebble Hatfield wrote:I notice when reading about permaculture there is a large focus on plants that produce fruit. Also vegetables. I'm curious about this because from a nutritional point of view fruit and veges are important but they don't supply the crucial fats and proteins, or even the amount of carbohydrates that most people need (that's a gross generalisation from the climate I live in - maritime temperate).
Just wondering how much people think about what they eat in relationship to permaculture.