Thanks for the snippets. None of that addresses my concerns in post #64. (And you have to be careful using human dietary guidelines for squirrels because of the difference in body size. For a grey squirrel to eat 6 tbsp per week of sweet potato would be like a 150-lb human eating 33 pounds of sweet potatoes per week; for a flyer, 175 lbs.)
First, your use of six tablespoons seems rather arbitrary. Why not four? eight? twelve? I fed my squirrels sweet potato this morning and weighed two random "chunks." The weight was 6 grams, or .21 ounces. Going on weight, not volume, if I fed this amount three times a week, that would equal .63 ounces. If there are two tablespoons per ounce, that means each tablespoon would weigh .5 ounces, so mine would eat a a little over 1/6 of the amount you used as reference. I think that 150 human could handle 5.5 pounds of sweet potato a week--of course that human might get sick of the thought of them rather than from them.
It's true this article is about Beta carotene in humans, but it stands to reason chemical reactions are chemical reactions. Regardless, you/we are basing our diets for our squirrels on laboratory experiments on rats. There can be vast differences there also (between species). Also, the Nutrient Requirements for Laboratory Animals that you cite, and I think you based your formulation for HHBs on, and the rest of the healthy diet on, bases its findings for rats on 15 grams per rat per day for maintenance, and while weights of species vary, the average rat seems to be about the weight of a gray squirrel. At 15 grams per day, the rat is eating about 1/4 of its body weight per week, not its body weight per week as we assume for squirrels. I assume your calculations took this into consideration. Otherwise, we might already be giving squirrels four times of every nutrient that they need. (assuming they actually DO eat their body weight a week).
Anyway, I thought this specifically addressed your concern about the interaction, particularly with lycopene, of Beta carotene with other cartenoinds:
The results of metabolic studies suggest that high doses [from the word "doses" I infer this means of supplements] of beta-carotene compete with lutein and lycopene for absorption when consumed at the same time (119-121). However, the consumption of high-dose beta-carotene supplements did not adversely affect serum carotenoid concentrations in long-term clinical trials (122-125).
Your link took me to a site selling supplements and I didn't see the last few paragraphs there.
I apologize. I pasted the wrong link. The information came from Oregan State University's Linus Pauling Institute which specializes in micronutrient research.
http://lpi.oregonstate.edu/infocente...s/carotenoids/
I don't see the point,
since you do not seem to ever read them, but here is the finding of most concern. If you want the other references I can look them up later.
It's difficult to maintain a civilized discussion with you if you insist on being so insulting. Of course, if I react I risk attack from higher powers, so I'll just let you know I'm trying.
"High intakes of either retinyl palmitate (42 µmol/kg diet) or beta-carotene (89 µmol/kg diet) depressed plasma and liver concentrations of a-tocopherol to about one-half the normal concentrations (Blakely et al., 1990). It seems probable that high concentrations of vitamin A in the diet interfere with the absorption of vitamin E. " [This is in rats; not humans.]
Again this is in humans, so you may discredit if you will, but it seems the idea that Beta carotene interferes with vitamin E is is quite controversial:
"Not all researchers agree that beta-carotene diminishes vitamin E supplies. "In most of the large-scale clinical trials involving beta-carotene supplements there has not been a significant effect on plasma vitamin E," argues Robert S. Parker of Cornell University."
Furthermore, the studies on rats used Beta carotene supplements, and as with its reactions with other substances, there might be great differences between how naturally occurring Beta carotene found in food and that in supplements might affect any other nutrient.
And finally, an irony is that some of the foods black-listed because you think they might interfere with vitamin E are also some of the ones ones highest in vitamin E:
"The richest source of vitamin E is wheat germ.
Other foods that contain a significant amount of vitamin E include:
• Liver
• Eggs
• Nuts (almonds, hazelnuts, and walnuts)
• Sunflower seeds
• Corn-oil margarine
• Mayonnaise
• Cold-pressed vegetable oils, including olive, corn, safflower,
soybean, cottonseed, and canola
• Dark green leafy vegetables like spinach and kale• Greens (beet, collard, mustard, turnip) sweet potatoes• Avocado
• Asparagus
• Yams
http://www.umm.edu/altmed/articles/vitamin-e-000341.htm
.
with sweet potato being one of the highest, if the the highest, vegetable sources:
http://ohioline.osu.edu/hyg-fact/5000/5554.html
Nutrient Requirements of Laboratory Animals, Fourth Revised Edition, 1995, Subcommittee on Laboratory Animal Nutrition, Board on Agriculture, National Research Council, National Academy Press: Washington, D.C. 1995 (p. 42)
Blakely, S. R., E. Grundel, M. Y. Jenkins, and G. V. Mitchell. 1990. Alterations in beta-carotene and vitamin E status in rats fed beta-carotene and excess vitamin A. Nutr. Res. 10:1035–1044.
These are, of course, from the same source, the NRLA, but thank your for taking the time to type them both out.