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Seems odd, considering cow milk contains virtually no vitamin D. It is often enriched with vitamin D, but that practice likely does not predate the evolution of

Seems odd, considering cow milk contains virtually no vitamin D. It is often enriched with vitamin D, but that practice likely does not predate the evolution of lactose tolerance.

StevePerkins 9y ago
When it comes to nutrition, the majority of unsourced information on web forums is made-up nonsense. Perhaps not maliciously in bad-faith (i.e. maybe OP really has heard this before)... but usually someone repeating something they heard 3rd or 4th-hand without any real fact-checking. Milk is high in vitamin D because it's intentionally added. Like iodine in table salt, or fluoride in drinking water. Obviously these things had no role in human evolution before they started in the 20th century.
- jessaustin 9y ago
  Vitamin D is only absorbed in the presence of fat in the intestine. Milk is a source of fat. Of course it isn't the only source of fat, but the hypothesized explanation is more plausible than you might think. I have observed 'seanmcdirmid to be a thoughtful commentator. It would be uncharitable to suggest that he thinks that USDA has regulated milk drinking for millennia. Most "1st-hand" nutritional research is also wrong. That has been the case for decades, which explains the field's relative lack of progress. The reason is that most nutritional research is funded by large commercial food interests.
seanmcdirmid 9y ago
Oops. You are right, I was thinking of calcium, which you can get from green veggies as well. I get confused because we had to deal with them all at once when my wife was pregnant.
Panino 9y ago
I know the subthread went in another direction, but: vitamin D increases the absorption of calcium. With minimal vitamin D synthesis from sun exposure in northern Europe, it makes sense that extra dietary calcium would be an evolutionary advantage. Hence, lactose tolerance. So OP's comment made sense even while confusing vitamin d and calcium.
- Tharkun 9y ago
  Hah, that's a direction I hadn't considered. That is indeed exactly why vit D is added to milk in the first place. The milk industry claims it's a good source of calcium, but fails to mention it's generally a poorly absorbed source of calcium. Hence the addition of vit D. Hard cheeses are generally very low in lactose, by the way, but I guess lactose intolerant societies are unlikely to discover this on their own.
  - seanmcdirmid 9y ago
    Lactose intolerant societies generally have cheese and other forms of curd. Also, babies are generally lactose tolerant regardless, losing this tolerance later.

Seems odd, considering cow milk contains virtually no vitamin D. It is often enriched with vitamin D, but that practice likely does not predate the evolution of lactose tolerance.

StevePerkins 9y ago

When it comes to nutrition, the majority of unsourced information on web forums is made-up nonsense. Perhaps not maliciously in bad-faith (i.e. maybe OP really has heard this before)... but usually someone repeating something they heard 3rd or 4th-hand without any real fact-checking. Milk is high in vitamin D because it's intentionally added. Like iodine in table salt, or fluoride in drinking water. Obviously these things had no role in human evolution before they started in the 20th century.

jessaustin 9y ago
Vitamin D is only absorbed in the presence of fat in the intestine. Milk is a source of fat. Of course it isn't the only source of fat, but the hypothesized explanation is more plausible than you might think. I have observed 'seanmcdirmid to be a thoughtful commentator. It would be uncharitable to suggest that he thinks that USDA has regulated milk drinking for millennia. Most "1st-hand" nutritional research is also wrong. That has been the case for decades, which explains the field's relative lack of progress. The reason is that most nutritional research is funded by large commercial food interests.

seanmcdirmid 9y ago

Oops. You are right, I was thinking of calcium, which you can get from green veggies as well. I get confused because we had to deal with them all at once when my wife was pregnant.

Panino 9y ago

I know the subthread went in another direction, but: vitamin D increases the absorption of calcium. With minimal vitamin D synthesis from sun exposure in northern Europe, it makes sense that extra dietary calcium would be an evolutionary advantage. Hence, lactose tolerance. So OP's comment made sense even while confusing vitamin d and calcium.

Tharkun 9y ago
Hah, that's a direction I hadn't considered. That is indeed exactly why vit D is added to milk in the first place. The milk industry claims it's a good source of calcium, but fails to mention it's generally a poorly absorbed source of calcium. Hence the addition of vit D. Hard cheeses are generally very low in lactose, by the way, but I guess lactose intolerant societies are unlikely to discover this on their own.
- seanmcdirmid 9y ago
  Lactose intolerant societies generally have cheese and other forms of curd. Also, babies are generally lactose tolerant regardless, losing this tolerance later.