Amazoniac
Member
The adsorption was a speculation based on what was mentioned before.1. How do you know how much calcium is absorbed from natural oranges/juice. They only tested fortified OJ. What form do they add to OJ in counties that fortify?
2. I don't think their criteria are useful because the concept of servings are based on mostly stupid nutritional recommendations.
3. I highly doubt that you can accurately compare the amounts of absorbed calcium from all these foods. As they say, they just took the values from dozen of publications, and probably used different methods to measure absorbable Kalzium from animal and plant sources.
Concerning the servings. You get about 100mg of Ca from 237ml of milk (why is about 50mg higher for yoghurt?). The Ca value is about 50mg for a serving of turnip greens or brassica like broccoli. So, to get the 300mg of absorbed calcium you apparently need you would have to drink about 700ml of milk. You would have to eat about the same weight of greens or brassica. I doubt that any human being (maybe with the exception of Trabis) can eat that much highly-indigestible stuff without drastic discomfort and digestive issues. Lots of people would probably also struggle with the Milch, but I think there is a higher probability of adapting to drinking half a quart of goat's milk than it is to eat over half a kilogram of greens. Provided oranges really have 30mg of calcium, and you could absorb say 15mg of it, you would absorb your 300mg by drinking 2 quarts of it. That would be awesome.
A standard orange according to the USDA weighs 140 g, 85 g being edible. Based on your publication, ~30 mg of Ki/100 g of this portion: about 25 mg of Ki per orange. If 5 oranges are eaten throughout the day with half being adsorbed (because it's efficient at low intakes), that would correspond to 20% of the daily uptake.
An argument to be made is: why would they fortify the juice if it provided a good amount? But as we discussed, part should remain with the pulp, something similar could occur if broccoli was juiced [], and when these are eaten, the chances of adsorption increase. The amount won't be high, but can be considerable at the end of the day.