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Given that meat is high in purines and the breakdown of purines ultimately results in a large amount of urate, the excretion of which is increased by Vitamin C, one might reasonably assume that we paleo folks would find benefit in supplementing ascorbic acid daily. This is only one of many ways that animals use the vitamin, but it's one whose need would scale up with meat consumption. The urate decrease from less fructose would probably be to some extent balanced out by an increase from purine nucleotide breakdown.

While the SAD may increase the need for Vitamin C for some other reason (due to the increased fiber intake maybe as well as massive fructose intake maybe?), I'm not certain that the dismissive attitude toward vitamin C that I see often in our community, such as it is, is warranted.

Dogs apparently endogenously produce roughly 18mg of C per pound of bodyweight. In times of stress, they produce quite a bit more. A 180 pound paleo werewolf abomination might then manufacture 3.24 grams of the stuff.

Given that we humans are incapable of any endogenous production, one may desire to supplement with this surprisingly non-toxic water-soluble vitamin in similar doses.

I would however recommend against consuming fructose-rich foods in order to obtain ascorbic acid, especially if one is attempting to lose fat, since fructose is one of the most lipogenic substances known. To say nothing of the fact that fructose increases urate levels itself.

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Im glad you asked this question, as I was going to ask a similar one with Vit C as an emphasis. I prefer to use my foods as supplements, but in what cases does strategic supplementation outweigh the negative effect of the food being consumed, i.e. taking in fructose, to get C. – Todd Jan 28 2011 at 0:09
shellfish. 20 clams = 42 mg; 12 mussels = 26mg; – MikeD Jan 28 2011 at 0:45

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Paleolithic man would have eaten fruits, maybe rose hips in the winter, and chewed on leaves and whatever was around. Sorry, but I don't see how an all meat diet is mimicking any paleo lifestyle, except maybe those in polar regions, and even the Inuit eat sea weed, berries and other things available in the harsh climate. I don't know how the idea of an all meat diet translates to paleo, when eating would have been very based seasonally. Further, we don't have truly carnivorous teeth nor do we have flat teeth which suggest purely herbivorous diets. We have the teeth of omnivores, so vitamin C should have easily come naturally to the paleolithic humans because they would have grazed on all kinds of things throughout the year.

I expect this to get downvoted, but that won't make any of what I've written. I grew up in the country, playing in fields and woods. As a kid, I learned quickly that you can pull out red clover petals and suck on the white ends to get some sugary sap, and we all experimented with sucking the sap out of tall grasses when we pulled the soft part of it out of the stalk. We chewed on the ends. Indigenous people in many places chew on leaves for medicinal or pleasant effects. All of this supplements nutrition.

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This is certainly true, but what I'm saying is that if a paleo individual wants to lose fat (and surely cutting out all fructose is the easiest way while paleo) then they're going to find themselves ingesting even less vitamin C than the average person, which may not be optimal. Clearly, the average person isn't taking 3 grams a day from food or any other sources, and there is evidence that even if they did, they wouldn't absorb it due to the competition for cellular uptake mentioned by Simibee. I think supplementation is consistent with optimal health and evolutionary biology. – Travis Culp Jan 28 2011 at 4:25
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All I'm saying is that an all meat diet, which I'm not knocking, isn't really paleo the way I see it. I also agree that cutting sugars is a good way to shed body mass (as opposed to water or muscle), but that again, it's not really how paleolithic humans would have lived. And they wouldn't have cared about their weight or belly fat, either. That's social conditioning. Rose hips can be found outdoors in the winter or via herbs shops/online, which would help supplement the diet without adding sugar. Orange peel has vitamin C. See where I'm going? I take supplements for some things, but C is easy – Rock_Paper_Shirley Jan 28 2011 at 4:33
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Wierdly, I find myself agreeing with both Travis AND Rock! – Eva Jan 28 2011 at 4:57
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And just to hammer this back to evolution, what we may need to ask ourselves is "If high vitamin C intake results in optimum health and strong immunity, what were our ancestors digesting which led to this adaptation?" or something like that. I would venture a guess that it wasn't soley meat. – Rock_Paper_Shirley Jan 28 2011 at 5:18
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You'd also have to ask yourself "does high vitamin C intake result in optimum health and strong immunity". That seems to be the more important question. So far, no evidence of this exists, and some contradictions; studies into high doses of C and colds, for example, do not show anything particularly significant. The assumption that high doses of C are beneficial needs to be examined before jumping into wondering how our ancestors got beneficially high doses of vitamin C - that might simply not be true. – pfw Jan 28 2011 at 15:03
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Ok so you have a hypothesis. Vitamin C will bring benefit. Sub-hypothesis: Heavy meat intake requires Vitamin C supplementation. What are your predictions with this hypothesis? How will you test them?

You must be aware of this study, the infamous Bellevue trial in which two men ate nothing but meat for a year without any supplementation and were in good health. Their meat intake was as high as would be possible (their entire diet) and their vitamin C intake was essentially as low as it could reasonably be, and they were fine.

So I'm curious to see how you square your hypothesis with this observation.

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is there any vitC in meats? i couldn't find any. – MikeD Jan 28 2011 at 0:22
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kidneys have some – mari Jan 28 2011 at 0:24
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You didn't really make a prediction or respond to the test. If vitamin C supplementation in the g/d level is necessary, how is it even POSSIBLE to eat only meat for a year? And if it's merely beneficial, what benefits do you predict? – pfw Jan 28 2011 at 11:52
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What other carnivores and other animals do metabolically isn't much of a guide for humans. We don't produce grams of vitamin c a day. Maybe that's a hint that we don't need grams of vitamin c a day? – pfw Jan 28 2011 at 11:52
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Oh, and one more thing. There are plenty of people in the modern day who have eaten meat-only diets for substantial periods of time with no obvious problems. I did it for a year, others here have done it for longer. So you have a population to make predictions and test hypotheses with - what would you propose? – pfw Jan 28 2011 at 11:53
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This is why it's important to eat organ meats.

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ok so we've got kidneys on the list. what are all the organ meats that have vitamin C? – MikeD Jan 28 2011 at 0:31
nutritiondata.self.com/facts/beef-products/3466/2 OK so 100 grams of raw kidney have 9.4mg of vitamin C, which means 42.7mg per pound. So in the 180 pound example, you'd have to eat 75 pounds of raw kidney a day to get the same amount as if you produced it yourself. – Travis Culp Jan 28 2011 at 0:37
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Shellfish! 20 clams = 42 mg – MikeD Jan 28 2011 at 0:41
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The problem using the Bellevue experiment and the SAD diet are similar in that they only apply to those who eat that diet. SAD eaters may need more vit C. ALL meat only dieters may need less. But for those in the middle, can we assume either applies to us? In fact, in both cases, we only know if people get scurvy or not but we don't know what is optimal. Since most humans actually do naturally prefer a varied omniverous diet, AND our dentition is designed for that, I am guessing that some vitamin C is optimal, even if it just means eating a few oranges per week and some veggies. I think people are going overboard with this fructose phobia. Yeah, don't eat a ton of it, but eating an orange twice per week is fine for most people.

Edited to add: Whoa, now here's something interesting! http://www.vitamincfoundation.org/forum/viewtopic.php?f=3&t=6086 Looks like about 30 % of the human population may be able to make enough vitamin C internally. Some people just don't get scurvy no matter what crap they eat! The rest seem like they will do fine as long as they eat meat which contains the hydroxyproline and hydroxylysine that we need vit C to make in the first place (thank you to the person who pointed this out in the other post, very interesting). Anyway, seems to me most will either be eating meat or getting vit C from fruit. Very few will fall through the cracks unless you are stuck on a boat at sea with mostly just biscuits. And even then, a certain percentage will make their own vit C and still not get scurvy.

I'm so glad this questions was asked as now I've learned two very interesting new things.

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You make some good points, but I'm interested in what is optimal for health and longevity, not what is necessary for survival. I'd hate to find out later on in life that some particular ailment might have been avoided were I to have taken a more ascorbic route. Seems like the logical thing to do would be to find out roughly how much we would manufacture ourselves were we still in possession of the ability, and then just ingest that amount. – Travis Culp Jan 28 2011 at 6:28
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That doesn't seem logical at all. You are ignoring the possibility that humans lost vitamin C synthesis for a reason and that high levels of intake actually are harmful. You've constructed a dietary Pascal's Wager with exactly the same flaw: if you pick wrong, you're wrong, and there's no clear right answer. – pfw Jan 28 2011 at 11:58
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Great link and info, Eva. I had no idea about the 30% who won't get scurvy. Geez we're a complicated animal. – Rose Apr 28 2011 at 15:27
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Are you considering vitamin C from the perspective of an antioxidant? If so, I would imagine that the system is to some degree self-regulating. Although a high purine diet may cause your body to excrete higher levels of vitamin C, don't forget that it will also increase production of uric acid, which is one of our most important antioxidants. Uric acid constitutes the antioxidant found in highest concentration in human blood, as it provides about half of the total antioxidant capacity of blood.

Equally, if you are following a moderate to low carbohydrate diet, the resulting stable blood sugar levels will decrease oxidative stress on your body. At the same time, your body's need for vitamin C is diminished, since vitamin C competes with glucose for entry into the cell via insulin receptors. Due to this mechanism, supplementing vitamin C to excess is far from harmless as it actually causes insulin resistance.

EDIT: "It has been noted that the loss of the ability to synthesize ascorbate strikingly parallels the inability to break down uric acid, also a characteristic of primates. Uric acid and ascorbate are both strong reducing agents. This has led to the suggestion that, in higher primates, uric acid has taken over some of the functions of ascorbate."

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This still doesn't account for the widespread endogenous manufacture of vitamin C by herbivores, omnivores and carnivores. That is interesting about the insulin resistance, however. – Travis Culp Jan 28 2011 at 1:45
Actually, (as my edited post explains) higher primates such as ourselves seem to be the exception to all other carnivores, omnivores and herbivores. I can only conclude that a moderate to low carb, high purine diet would be optimal. – Simibee Jan 28 2011 at 15:32
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The knockout of uricase is thought to amplify the lipogenic qualities of fructose digestion. For those who don't ingest fructose, and/or don't want to gain fat from it, this is not beneficial. – Travis Culp Jan 28 2011 at 19:32
thanks, i had forgotten that uric acid has reducing capacity. still, try to make some collagen using urioc acid. LOL. i love biochemistry. – coprophagous Dec 20 2011 at 7:41
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Depending on how much we need for real, broccoli seems like a real winner ~3 oz will get you almost 100%DV. If we don't need the DV there are some promising amounts in spinach and seaweed. You could also go wild with some dandelion greens.

Vegetables high in vitamin C include green peppers, broccoli, Brussels sprouts, cauliflower, cabbage, raw and cooked leafy greens, such as spinach and kale, as well as potatoes and winter squash. Livestrong

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I don't think the DV is based on what it takes to prevent scurvy, not what produces optimal health. – Travis Culp Jan 28 2011 at 0:38
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i guess its a matter of whether we think large doses of vitC is optimal. it could just be that mega doses help in some way deflect some of the diseases of civilization that dont apply when we eat paleo? so if i stave of scurvy by eating a few clams is that all i need to pursue optimal health or do i get some further benefit from large amounts of C? – MikeD Jan 28 2011 at 1:04
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When people talk about vitamin C, I think a megadose is like 50 grams+ a day. 3 grams is pretty reasonable, but perhaps low, given how much various animals of similar size produce on their own. I've read that if you adjust the weights to line up with humans, most animals produce between 3 and 15 grams a day. – Travis Culp Jan 28 2011 at 1:26
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Though fructose may constitute a legitimate concern, couldn't low-sugar fruits (strawberries, grapefruit, lemon or lime juice added to marinades or sauces, etc.) provide a significant dose of Vitamin C without promotion of weight gain?

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Personally, I'm of the opinion that no other factor affects adiposity in nearly the same amounts as fructose and that it makes no sense to include it in one's diet unless one is at least happy with their current degree of adiposity. One large kiwi ( nutritiondata.self.com/facts/… ) has 85mg, so you're still looking at 38 large kiwis to get the aforementioned dose, which would be roughly 150grams of fructose alone. It's simply not feasible. – Travis Culp Jan 28 2011 at 1:12
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Supposedly raw meat contains the compound that our bodies make and need from Vit C. Sort of like the pre-cursor to Vit C. So our bodies get what they need from the meat and bypass the need for C.

I don't know a lot about this, or whether it is fact or speculation. If anyone knows, please chime in...

This is the basic idea: http://www.rawpaleoforum.com/infonews-items/vitamin-c-and-carnivorism/

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That Bellevue all-meat trial that pfw referred to mentions that raw meat prevented scurvy. I don't doubt that it's possible, but how many of us are realistically going to do that? I'm sure as heck not going to. – Travis Culp Jan 28 2011 at 1:14
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IIUC, it doesn't have to be raw -- medium will do. – Ambimorph Jan 28 2011 at 4:14
This idea doesn't hinge on eating an all meat diet, or all raw meat. I eat lots of rare meat and assume many others do to, just as a taste preference. – Hannah Jan 28 2011 at 15:14
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the amount of vitamin c one needs for optimal health varies. in other animals vitamin C is an acute phase reactant and will easily increase twenty to thirty times if the animal is duly stressed. in humans of course this is impossible since we cannot ever consume much more that the ridiculously low RDA level that while prevents death due to the rapidly fatal scurvey will not prevent gingivitis and atherosclerosis in up to if not more than thirty percent of humans. personally i consume one gram a day in addition to the 250 milligrams i get in fresh raw fruit and vegetables and have done very good with my vascular health. even the pinguecula that are never supposed to just go away are almost gone. in scientific studies dogs are used to correlate the effects of diet on atherosclerosis yet dogs manufacture vitamin C. what the studies will not mention is that only one in 400 dogs can get atherosclerosis and their vitamin c levels are UNPUBLISHED. how damned convenient is that if you are trying to sell a statin drug?

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let us all remember that sugar and vitamin C are so closely related biochemically that in the presence of sugar vitamin c is not absorbed. so even if we drink that sweet orange juice that is fortified, we still loose big time. – coprophagous Dec 20 2011 at 7:48
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It's not not absorbed. They compete but that's not the same thing. Lack of insulin depletes vitamin C and increases the need for it. – JRAC Dec 20 2011 at 12:36

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