Plant-based and Nutrition: B12, Calcium, Vitamin D
Anyone who chooses to eat a plant-based or ‘vegan’ diet will be used to answering questions about nutrition – usually in the form of where or how they ‘get’ a particular nutrient. In ‘The Pleasure Trap’, Doug Lisle and Dr Alan Goldhamer suggest that our obsession with ‘getting enough’ comes from our evolutionary past where food was more scarce. They point out this likely works against us nowadays, as the health problems facing our society are mostly due to excesses, rather than deficiencies.
It’s also worth mentioning, before addressing any of these commonly posed questions, that T. Colin Campbell has written a second very good book called ‘Whole’. He argues, rather convincingly, that our current emphasis on isolated nutrients is flawed. It’s not the most thrilling read, unless you’re similarly geeky about this as I am, but certainly worth a look if you’re so inclined.
I’ll need to split this into a few posts. Because nobody has that kind of stamina. I’ll give protein its own special post because that’s a big one.
So let’s start with something fundamental. Vitamin B12. Everyone who’s eating plant-based or vegan MUST supplement with B12. B12 is a very interesting and mysterious thing. Nowadays the only reliable source without fortification is animal products. It’s possible there may have been some amounts present in the soil or even in some plant foods like mushrooms in the past. What’s really interesting is that our stores last for ages (literally years, I’ve seen estimates range anywhere from 5 to 30 years), so while it’s certainly something we need, it’s seemingly something we don’t need to get all that often.
That having been said, there’s consensus that supplementation is required, if you’re not eating animal products. And there do not seem to be any downsides to that either. Again being the mysterious thing that it is, B12 is absorbed in a strange way. Even if we take large amounts, only a very small percentage (about 1.5mcg and then 1% of whatever’s left) can be absorbed at any one time. Without going into all the whys and wherefores, taking a B12 supplement of 5000mcg once a week, or 2500mcg twice a week is recommended.
Calcium is a mineral found in the ground. So it’s absorbed into all plants while they grow. Some plants do have more than others, but even apples and potatoes contain calcium. When you think about it, it doesn’t make any sense that we would need to drink milk from another animal to get this. Where does the cow get the calcium that ends up in its milk? From the grass it eats, which is just another plant, after all. Animals that get their calcium from plants have massive, strong bones: elephants, rhinos, and horses, for example. So it makes sense if we can get enough from eating plants too. This is especially the case when we eat smaller amounts of protein and salt, which cause our bodies to lose calcium.
Vitamin D has received a lot of attention in recent times. Like Vitamin B12, it’s also a bit of an interesting one. It seems unlikely that food has ever been a major source, and it’s still not even today. Fortunately, our bodies make all we need when we have adequate sun exposure. So this is the best way to be getting it. Directions for exactly how and when to do this can be found easily enough online (see nutritionfacts.org, for example) so I won’t go into the details here.
There’s a bit of debate about how much is needed, and whether to supplement. Obviously in New Zealand during winter it’s difficult to get regular sun exposure. So potentially a supplement could be helpful. However, there’s not really any evidence I’m aware of to show this just yet, and presumably New Zealanders (and others in less tropical climes) have been having similar sun exposure during winters for generations now without any glaringly obvious signs of Vitamin D deficiency. So for now at least I’d say supplementation is more a personal preference thing. I have some and take them very infrequently just to hedge my bets.
Alright, enough for now! More about nutrients another time.
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