Most people who take vitamin supplements take them all at once, usually at the end of the day after their last meal.
Other than the risk of overloading your digestive tract and most of them being passed instead of used, this isn’t a bad strategy… especially if your vitamins are fat-soluble and you’ve had a large, fairly-fat-rich meal for dinner. Sure, some will likely get passed, but much of what doesn’t directly go to your bloodstream for use could them get stored in whatever fat you end up storing, to be released in your bloodstream later when that fat is tapped for energy. (This in fact is why vitamin capsules contain oils: The oils are digested and stored as fat, and the vitamins absorbed can come along for the ride.)
This is beneficial for runners, triathletes and other endurance athletes. When they go to train soon thereafter, any of that fat that’s aerobically burned will also release those stored vitamins for use… at a time when their body may actually need it.
Now, that said, while I’ve talked about vitamins that can and should go together (like Vitamin K2 and calcium), some nutrients don’t go with other nutrients. And one key nutrient to keep in mind is L-theanine.
Many don’t take L-theanine, though I do, because theanine is an important nutrient for the successful absorption of magnesium. Our bodies can provide a limited supply, though too limited to fully absorb any supplemented magnesium.
However, L-theanine’s digestion tends to block the digestive absorption of other vitamins. So if you take L-theanine with other supplements, you effectively are cancelling out the absorption of those other vitamins. You just wasted some vitamins. Plus, if you eat any nutrient-rich foods, taking L-theanine with it can block those nutrients from being absorbed as well.
This is why it’s recommended that L-theanine be taken between meals, on its own. You want to cede the floor, so to speak, of your digestive tract to that L-theanine supplement so it not only gets fully absorbed, but it will not interfere with the absorption of your other vitamins later.
Keep in mind that a key natural food source of L-theanine is green tea. So you also want to avoid eating any nutrient-rich foods when drinking green tea. Ditto any mushrooms rich in L-theanine… you probably want to stick to eating your mushrooms with your favorite garbage foods, or accept that nutrients in that meal may not be as well absorbed.
Garbage foods? Well, while L-theanine interferes with absorption of other vitamins taken at the same time, it doesn’t interfere with digestion in general. You can eat anything with it… just the nutrients in that food may be blocked from absorption.
So remember when I mentioned fat-soluble vitamins joining with stored fat? One type of food you can comfortably consume with L-theanine is simple fat, like oils.
I like to drink hot water infused with coconut oil. While the lipids and fatty acids in coconut oil itself have valuable anti-fungal and anti-viral properties… the coconut oil itself has no nutrients outside of its fat content. I could comfortably take L-theanine with that oil-infused water, knowing I not only won’t lose any additional nutrients from combining them… but that if the absorbed saturated fat is stored, theanine can be stored along with it.
But won’t L-theanine interfere with other vitamins later? L-theanine only interferes with the digestion and absorption of other vitamins. Once the theanine is in your fat-stores or your bloodstream, theanine and other vitamins can co-exist without a problem. Again, theanine in fact is valuable to the utilization of magnesium. Once both are in the bloodstream, they complement each other. The key is to just get all your needed vitamins properly digested and absorbed first.
Also, even though you shouldn’t be eating this garbage, you can take L-theanine with many fried or processed foods. These are typically so devoid of vitamins and nutrients that L-theanine probably won’t interfere with the absorption of anything substantial. You will get whatever protein, carbs and fat are in it, but what little vitamins there are probably will be flushed. But again, you shouldn’t make a habit of eating this food anyway, and your nutrients should typically come from fresh, whole, unprocessed foods.
Few vitamins interfere with one another’s absorption the way L-theanine does. But it’s valuable if and when you learn of a vitamin you take that does that you take those offending vitamins separately, between meals or not during nutrient-rich meals, when you do. This is why I take L-theanine in the late morning or afternoon between meals, at least 2 hours after the last meal and no less than 90 minutes before the next meal. And then I take the rest of my vitamins after dinner.