Just to recap from a few years ago, there are two well studied villages in Tanzania. One has a diet which is subsistence agriculture and so complex starch based, the other is also mostly starch based but supplemented with half a kilo of fish a day. Their daily food intake is approximately described in this Lancet paper:
"Daily energy intake was similar in the two populations (2196 kcal [9·19 MJ] in the fish-diet group vs 2109 kcal [8·82 MJ]). There was no difference in salt intake (4·4 vs 4·0 g daily). In the fish-diet group, 23% of energy intake was from fish with consumption of 300-600 g daily (three to four fish meals per day). Among the vegetarians, most energy was derived from complex carbohydrates (82% compared with 70% in the fish-diet group) such as maize and rice. The proportions of energy derived from protein were 11% and 18%, respectively, and those from fats 7% and 12%. "
The vegetarians are as close to an ideal version of a low fat vegetarian diet as you can get. I don't know much about Ornish's ideas but I'm guessing this comes as close to doing it "correctly" as you can. Exercise too!
The fishermen on the lake shore seem closer to the Kitavans in their macronutrient intake. Still high carb, but not quite up at the 82% of calories mark eaten by the vegetarian farmers...
Using blood pressure as a surrogate for CV health, the fish eaters appear to beat the complex carb group quite convincingly:
So, if you are on an extremly low fat vegetarian diet and your blood pressure isn't doing what it's supposed to do, don't blame yourself. Eat some animals.
Pauletto's group think it is specifically the omega three lipids which have the beneficial effects on BP, but I'm not so sure. If you eat a diet based on fish and seal alone, and virtually zero carbs, you still get this increase in blood pressure with age. Despite the omega three fatty acid intake being very high.
The comparison comes from Paal Røiri's 2005 discussion paper "Eskimo-kostholdets betydning for dødeligheten av hjerteog karsykdommer". We have this table of blood pressure changes with age, rising from just over 100mmHg systolic in childhood to around 150mmHg over the age of 60.
Either extreme does not appear to be ideal. It looks like the upper tolerable limit of unrefined complex carbs seems to be some where above 70% of calories but below 80%. Living down at 4% might not be perfect either. But I digress.
The striking difference between the two Bantu groups is in Lp(a) level. Obviously the vegetarians have higher Lp(a) levels than the fish eaters, as you would expect from their slowly rising blood pressure with age.
You can see that the vegetarians have a median value for Lp(a) of 27mg/dl where as the fishermen have a median of 14mg/dl.
The assumption is that the high Lp(a) is bad and is furring up their arteries and putting up their blood pressure as they age.
Probably genetic. Bad genes mean the farmers have short kringle IV repeats and so their high Lp(a) sets about giving them their just desserts.