Vitamin D: Cholecalciferol supplements are the most effective, especially in women.

Vitamin D women: cholecalciferol supplements? The best

The positive effects of vitamin D supplements depend on several factors, such as the form of the vitamin and the timing of administration, but also on gender, genetics, and, to a lesser extent, the body mass index of those consuming them. In fact, according to recent research, women absorb the vitamin more than men, and supplements of the D3 form are more effective than those of vitamin D2, especially when consumed every 2 weeks.

These are the findings of a study published in the journal BMC Endocrine Disorders by researchers at the King Faisal Specialist Hospital and Research Center in Riyadh, Saudi Arabia.

The two most important forms of vitamin D: cholecalciferol and ergocalciferol

The term vitamin D refers to two precursors with similar biological activity: D3, also known as cholecalciferol, and D2 known as ergocalciferol. Both D3 and D2 are inactive but are converted in the liver and kidneys into 25(OH)D, the storage form of the vitamin, and into 1,25(OH)2D, the active form. Blood determination of 25(OH)D is the most accurate method for estimating the vitamin's reserve status in the body. Vitamin D is essential for magnesium and phosphate metabolism, stimulates and promotes calcium absorption and bone mineralization. 

Its deficiency in children causes numerous adverse events, such as growth retardation and rickets. Adults with severe vitamin D deficiency manifest bone fragility (osteomalacia), muscle weakness, and bone pain. These symptoms are routinely seen in elderly patients on vitamin D-poor diets, individuals with liver or kidney disease, reduced vitamin D absorption, or deficient exposure to sunlight. In addition to bone health, it is now established that levels of this vitamin may also reduce the risk of developing autoimmune diseases, infections, and type 2 diabetes. Only a few foods of animal origin contain significant amounts of vitamin D. 

In particular,cod liver oil, some fish such as salmon and herring, liver, eggs, butter, and fatty cheeses. In addition to getting vitamin D from foods, the human body can produce it through a series of reactions that begin with the action of sunlight on the skin. In some countries therefore, especially during the winter months, vitamin D deficiency is very common, in which case dietary supplements can help to increase its intake. Both vitamin D2 and vitamin D3 are available as supplements for any age group.

The efficacy of vitamin D2 versus D3 continues to be a matter of debate, although both forms would be effective in preventing and treating diseases caused by vitamin D deficiency by ensuring adequate 25(OH)D levels.

Is the D3 form more efficient than D2?

The purpose of the new study was precisely to shed light on the differences in vitamin D variants, revealing how the effects of supplements based on the D2 and D3 forms on the level of 25(OH)D in the blood depend on factors such as dosage, time of treatment, and gender. 

Specifically, the study revealed that although all types of supplementation were able to increase the blood level of 25(OH)D, this metabolite was higher in subjects who had received vitamin D3, compared with those who had consumed the D2 form, and, among the former, the highest concentration of 25(OH)D was found in those who had taken the supplements every two weeks. In addition, vitamin D3 absorption was higher in women than in men: the former showed a 22% higher absorption rate than men, and a 49% higher bioavailability. 

These differences appeared to be due to a greater presence of vitamin D-binding proteins in women, especially in those who were taking oral contraceptives, or in those who were on hormone therapy in the postmenopausal period, suggesting a relationship with female hormones. According to the same researchers, therefore, the differences between men and women could be related to a difference in the absorption of the vitamin, but also to the level of vitamin D-binding proteins, a faster metabolism of the vitamin itself, and, probably, also to a higher level of body fat.

In fact, body mass index (BMI) was also found to be a significant factor for D2 levels, but not D3, and only during the first four weeks of treatment. However, the link between BMI and response to supplementation was not clarified. During data collection, it became apparent that subjects with specific gene variants manifested lower increases in 25(OH)D, suggesting that, in some subjects, low amounts of this molecule were due to genetic factors rather than diet and lifestyle. 

The study also showed that participants who had received only D2 manifested a decrease in D3 levels, as shown in previous studies. According to the researchers, the mechanism underlying this phenomenon is not due to D2 supplementation but is simply a response to increased 25(OH)D levels.

Some details of the study

To carry out the study, 269 subjects between the ages of 18 and 60 (41 percent male and 59 percent female) were selected who were not taking vitamin D supplements, consumed more than one serving of milk per day, or were exposed to the sun for at least 10 hours per week. The researchers divided the participants into groups that followed different supplementation protocols: some subjects received daily vitamin D2 or vitamin D3 supplements, others a combination of the two forms. 

Other groups had followed D2 or D3 supplementation every two weeks, others every four. One group of subjects had also received a daily placebo. All participants, except those in the placebo group, took a total vitamin D dose of 250,000 IU at the end of treatment with dosages ranging from 2,000 IU for daily supplementation to 50,000 IU for supplementation every four weeks. 

The researchers drew and analyzed each participant's blood before treatment, then after the start of supplementation for the first four days, then after seven, and every two weeks, measuring 25(OH)D levels.

More efficient integration for women

According to the researchers who conducted the study, the effects of vitamin D2 and D3 supplements on 25(OH)D level are due to different factors. Specifically, the supplements were found to be more efficient in women than men, and vitamin D3 supplements increased 25(OH)D levels more than those containing D2; the latter also acted more when administered daily; as opposed to the D3 form, which was more effective when administered every two weeks.

D3 Drops: the supplement from Omegor

D3 Dro ps is a dietary supplement that provides 400 IU of cholecalciferol (the D3 form of vitamin D) per drop. The Omega 3 supplement, manufactured by Omegor, can be used in all cases of increased need or decreased dietary intake of vitamin D.  

Source: Hammami, M.M.; Yusuf, A. "Differential effects of vitamin D2 and D3 supplements on 25-hydroxyvitamin D level are dose, sex, and time dependent: a randomized controlled trial." BMC Endocrine Disorders.