Bioavailability

Hello, which vitamin is good to take with vitamin D for better absorption? Thank you.

The absorption of vitamin D is influenced by vitamin K2. If the gut microbiota does not produce enough of this substance, supportive supplementation is advisable.

Hello.

In the context of plant-based calcium sources, kale, pak choi, and broccoli are becoming increasingly discussed. What is your opinion on these foods in terms of calcium? I calculated the volume of absorbable calcium in broccoli, and it performs better than cow's milk. I am also moving away from recommending poppy seeds as a quality source because its absorbability is, in reality, very low, as mentioned here: https://www.evahajkova.com/cs/jaka-je-absorbce-vapniku-z-rostlinnych-zdroju-vyjadreni-k-maku, and there is also a risk of high cadmium contamination.

Thank you.

The absorption of minerals from food is not only a complex issue but, primarily in terms of numerical expression, highly relative. Too many factors come into play for it to be meaningful to express the level of utilization of each element; therefore, be cautious not only in adopting any values but especially in applying them in practice. The bioavailability of calcium is generally significantly lower from plant sources than from animal sources, so more effort is needed in plant-based diets to optimize the whole process. Essentially, this involves reducing fiber content and avoiding higher concentrations of other antinutritional components, but it also makes sense to maintain a balance with the intake of magnesium, care for the function of the gut microbiome, which significantly contributes to calcium metabolism, ensure adequate calciferol levels, and support metabolism through physical activity. The higher the proportion of plant-based foods (and thus calcium sources) in our diet, the higher the demands we place on the body to activate adaptive mechanisms tasked with maintaining balance. An extreme in this regard is a vegan diet, where it makes sense to address every "detail," as practice shows that indeed there is a challenge in ensuring adequate calcium with all its consequences. Do not address heavy metals in the mentioned food sources, as this factor depends on soil quality and crop cultivation methods, and it does not make sense to generalize it.

Good day.
In the lesson, you mentioned that liquid forms of vitamins do not have higher absorption rates than powders. Are there any studies on this? It mainly concerns fat-soluble vitamins like vitamin D. In the case of a tablet, you need to consume some fat for the vitamin to be absorbed correctly, whereas with a vitamin dissolved in oil – that is, in drops – this is not necessary.
Thank you for your response.

The issue of nutrient absorption is a complex problem, as the process is influenced by a variety of factors - the chemical form of the substance, its binding to substances that promote absorption, the combination of the supplement with food or its consumption on an empty stomach, the age of the user, their metabolic profile, and health status... Furthermore, there is a difference whether you simulate conditions in the laboratory (in vitro) or try to observe in living systems (in vivo) the rate and level of nutrient absorption from food or supplements based on their release into the bloodstream. Generally speaking, liquid forms of supplements are absorbed more quickly than tablet forms (due to the time-consuming nature of disintegration) - however, this information does not mean that they are absorbed better or in greater quantities, it only addresses speed. Tablet forms of supplements are generally recommended to be taken with meals, where, in relation to the content of fat-soluble substances, it is likely that the diet includes a certain amount of fats, which positively influences the absorption of these substances. At first glance, it might seem that the liquid form is more advantageous (and it is certainly faster) - typical examples are liquid forms with calciferol. However, this is only theoretical information based on the evaluation of the situation under in vitro conditions.