The influence of humic and fulvic acids on the absorption of selected vitamins in the everted gut model

Abstract

Nutritional deficiencies and illnesses are prevalent in society and there is a need to prevent them from occurring. The use of natural or complementary medicine when compared to the use of conventional western medication has increased in recent years. Complementary and natural medication preparations are however often unregulated and are not required to adhere to the strict safety and efficacy regulations enforced by the South African Health Products Regulatory Authority for prescription medication. These products are easily accessible to the public because they do not require a prescription and are often marketed as “safe” based on their natural ingredients. Many of these natural medications have unfounded claims of “benefits without side effects”. Humic acid and fulvic acid preparations have been reported to have antiviral, anti-inflammatory, antibacterial and profibrinolytic properties, however their efficacy may be overstated and therefore there is a need to investigate the claims regarding these natural products. The aims of this study were to evaluate the potential benefits of humic substances, and to determine the effects on the intestinal absorption of water-soluble vitamin when in the presence of humic substances. The method of choice for the evaluation of the effect of humic and fulvic acids on water soluble vitamin absorbance was an ex vivo method using the everted mouse gut model. Liquid chromatography tandem mass spectrometry (LC-MS/MS) was used to quantitate vitamin absorption. The absorption of different water-soluble B vitamins in the gastrointestinal tract (GIT) are affected by a number of factors including solubility, complexation ability, molecular size, the GIT region and the transporters available at the site of absorption. The influence of absorption of nutrients when taken in combination with humic substances was investigated and it was found that humic acid negatively affects absorption of most water-soluble vitamins while fulvic acid displays favourable absorption of select vitamins. There are potential benefits of fulvic acid in aiding nutrient absorption for treatment of nutritional deficiencies. Applications of humic acid as an additive in nutritional supplements is not recommended and should be avoided. This project set out to evaluate the potential benefits of humic substance supplementation in combination with B-vitamins but the results indicate that humic acid provides no benefit and fulvic acid, despite increased absorption of select vitamins, should be used with caution to avoid selective vitamin uptake.