Supplements are often recommended to be taken with food but I prefer to take mine on an empty stomach, soon after I wake up. I never eat breakfast and fast many days so there is no way I could take them with food every day. I drink lots of water, 1-2 gallons daily and at least 1/2 gallon with my vitamins. I take a multivitamin, vitamin C, calcium, fish oil, glucosamine chondroitin and sometimes psyllium husk fiber. I know some vitamins are only soluble in fat, but I figure the fish oil should provide enough. Is part of the reason food is so often recommended with pills to reduce possible stomach upset? That is not an issue for me. Am I getting as much benefit from my supplements as if I took them with food? If not, how much difference does it make?
Why do you not eat breakfast (the most important meal of the day) and fast most days?
Anyway, the human body has a complex endocrine system which, among other functions, best enables it to absorb nutrients when primed for active digestion, vitamins are best absorbed into the body when taken with food. Several vitamins and minerals show enhanced absorption when directly interacting, such as vitamin D and calcium. A few water-soluble vitamins such as the B-family of vitamins can cause mild stomach upset unless taken with food; while vitamin C, an acid, can erode the lining of the stomach if not buffered with food. Fat-soluble vitamins such as vitamins A or D actually require some natural food oils to be absorbed into the body at all.
I'm never hungry early in the day and it just works better for me to eat only once or twice in the afternoon and evening, and I don't fast most days but about one or two days a week average, for various reasons.
I'm wondering if the psyllium husk fiber (carbohydrates) and fish oil (natural food oil/fat) are "food" enough to sufficiently aid vitamin absorption. It actually isn't even considered fasting when I take those. When I take all my supplements with all the water that is recommended with them I am full and there wouldn't be room for an actual meal at that time anyway. I could spread them out through the day but then some would be on a completely empty stomach. Both forms of calcium I take (citrate and carbonate) have vitamin D and my multivitamin also has both calcium and vitamin D.
When I was researching a supplement on the Linus Pauling Institute site from Oregon State University, the recommendation was to take on an empty stomach, but the bottle (I think it was for Alpha Lipoic Acid, but not sure) said to take with meals....so I would think you would have to research each supplement to be sure!