I just tried to post this question but for some reason the text did not show so I'm trying again.
An elderly relative moved in with me about a year ago and I have fed him largely according to the paleo diet especially with regards to fats. He’s been eating 2 helpings of oily fish a week and no vegetable oils apart from some olive oil. I normally cook with butter, lard and olive oil. When he moved in he had had glaucoma (high-tension POAG) in one eye for some years and it was all well under control. About 9 months or so after he moved in with me he went for a routine check-up and found the POAG has very suddenly got much worse and is now rapidly progressing in both eyes. I searched online for any pointers and was alarmed to see the study cited by Chris Masterjohn at http://onibasu.com/archives/cl/20320.html (full text at http://ajcn.nutrition.org/content/79/5/755.full ). This study found a diet high in n−6 and low in n−3 polyunsaturated fats to be associated with a reduced occurrence of POAG, particularly high-tension POAG. They say “Our study findings are thus consistent with the hypothesis that greater dietary n−6 fat intake leads to greater availability of the n−6 prostaglandins (such as prostaglandin F2α), which may help to maintain IOP at levels that are less harmful to the optic nerve and thereby reduce the occurrence of POAG.” I am completely appalled that I may have caused his good eye to become dangerously high in pressure. It is possible he will lose his sight.
The question is what to do now? I don’t have the medical education to understand the details of the paper, which I assume is a good one because Chris Masterjohn refers to it. I’ve stopped giving him oily fish and he takes some omega 6 fats every day but I don’t know how to proceed in the long term. There are studies showing that omega 3s are good for glaucoma and anyway it’s necessary for basic health. I think the study indicates that it’s the ratio between the omega 3s and the omega 6s that counts but I am not sure of this as I can’t understand most of it. I do notice that there is some indication (in the discussion section) that low fat diets may be altogether better for glaucoma, although the evidence on this is not certain. Anyway if it is just a matter of ratio between omegas 6 and 3 I certainly don’t know what the ratio should be, or how to achieve it.
Yes I know I need professional help but I have not been able to find it. Where I live in the UK it is hard enough just find a paleo-friendly doctor. Finding one who is willing to engage with this study is impossible. They have their set protocols for common complaints like heart disease and are not interested in devoting time to looking at preliminary studies like this one. “We need more studies/evidence” may be a sound professional stance but I don’t have that kind of time.
Any helpful links gratefully received.
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That study is junk. They're fishing for hypotheses and they found an incredibly weak correlation and latched onto it. The question is has anybody followed up that paper… and Web of Science shows 27 citing articles. Just a couple I scanned quickly…
Nothing really significant in terms of the omegas, but when they looked at oily fish and walnuts, those produced the only statistically significant results. Higher consumption was associated with lower rates of POAG. Oh, and if you worked as a farmer in your lifetime, that was also associated with POAG.
No statistical significance to the omega-6:3 ratio. What was significant? Retinol and magnesium.
So I really don't think you paleo-esque diet with fish was the cause of the problem. I would wager it was just natural progression of the disease.
Glaukoma is known to be associated with hypothyroidism in elderly males (1). A low-carbohydrate paleo diet can be a cause of hypothyroidism.
The high meat-content of palo diets is problematic due to its high iron content. Excessive iron causes oxidative stress and is associated with aging and many degenerative disorders. Glaucoma patients are known to have lower zinc and higher iron levels in their eye fluids (2). Oysters are a rich source of zinc. So is liver, where iron is balanced with higher zinc and copper levels. It is also an extremely rich source of Vitamin A and B-vitamins. Supplementation with B12 had no effect on intraocular pressure, but did stop progression of visual field loss (3). Liver is a great source of B12.
Magnesium supplementation was found to alleviate visual defects in glaucoma (4). Soaked buckwheat (i.e. buckwheat pancakes), cocoa, molasses, well-cooked kale and orange juice are fine sources of magnesium.
Glaukoma patients were found to have lower thiamine (vitamin B1) levels (5). Soaked oats, buckwheat, liver and pork are good sources of thiamine. 1L of orange juice daily will also supply the RDA of thiamine.
Omega-3-fatty acids are even more susceptible to oxidation than omega-6 fatty acids (due to their higher double bond number). A diet low in overall PUFAs will reduce the susceptibility to oxidation. Coconut oil has barely any PUFAs and is devoid of omega-3 PUFAs.
Glaukoma is also associated with smoking, diabetes and certain drugs. These things should be monitored by his doctor.