What are the normal serum levels of vitamins in men versus women?

From the Guidelines

The normal serum levels of vitamins in men versus women can be determined by their recommended dietary allowance (RDA) values, which vary by vitamin and sex, with men generally requiring higher amounts of vitamins such as A, C, and E compared to women. When considering the normal serum levels of vitamins, it's essential to look at the most recent and highest quality studies. According to the study by 1, the current intakes and goal recommendations for various vitamins in men and women are outlined. For example:

• Vitamin A: men require 900 µg/day, while women require 700 µg/day, as stated in the study by 1.
• Vitamin C: men require 90 mg/day, while women require 75 mg/day, as stated in the study by 1.
• Vitamin D: both men and women require 10-20 µg/day, with a recommendation for older adults to take a daily 15 µg vitamin D supplement all year round, as stated in the study by 1.
• Vitamin E: both men and women require 15 mg/day, as stated in the study by 1. It's crucial to note that these values are based on the most recent study available, which is from 2022, and that individual needs may vary depending on factors such as age, sex, and overall health. Some key points to consider when evaluating vitamin intake include:
• The body's ability to handle higher amounts of water-soluble vitamins (B and C) compared to fat-soluble ones (A, D, E, K)
• The importance of consulting a healthcare provider before significantly altering vitamin intake, especially if taking medications or having health conditions
• The need for regular monitoring of iron status in older adults to identify those with poor iron status and avoid adverse health effects, as stated in the study by 1. Overall, it is essential to prioritize individualized nutrition recommendations based on the most recent and highest quality evidence, taking into account factors such as age, sex, and overall health, to ensure adequate nutrition while avoiding potential toxicity.

From the Research

Normal Serum Levels of Vitamins in Men versus Women

• The normal serum levels of vitamins in men and women can vary depending on several factors, including age, diet, and lifestyle 2.
• Daily iron and folate intake should be higher in menstruating women than in men of similar age, while lower total intake of vitamins A, B, E, K, and zinc are based on body size, and recommendations are usually lower in women compared to men 2.
• There is no consensus on the cut-off points for vitamin B12 and its co-markers, such as folate, holotranscobalamin, methylmalonic acid, and homocysteine, with broad ranges of cut-off points identified in different studies 3.
• The biomarker status of folate, vitamin B12, vitamin B6, and riboflavin decreases significantly with age, and homocysteine concentrations progressively increase with age, with higher values in boys compared to girls aged 15-18 years 4.
• Serum 25-Hydroxyvitamin D levels can vary widely depending on genetic and lifestyle factors, and a desirable range of 20 to 40 ng/mL (50 to 100 nmol/L) has been proposed, with slightly lower levels potentially sufficient for some infants and adults 5.
• Sex differences in requirements for micronutrients are inherent and influenced by body size or macronutrient intake, with different dietary reference values (DRV) provided for males and females for some micronutrients, and separate DRV provided for pregnancy and lactation 6.

Vitamin-Specific Levels

• Vitamin B12: cut-off points range from 100 pmol/L to 350 pmol/L 3.
• Folate: serum folate levels range from 3.7 nmol/L to 15.9 nmol/L, and red blood cell folate levels range from 124 nmol/L to 397 nmol/L 3.
• Vitamin D: a desirable range of 20 to 40 ng/mL (50 to 100 nmol/L) has been proposed 5.
• Homocysteine: concentrations progressively increase with age, with median values of 5.6.3, and 7.9 μmol/L for children aged 4-10 years, 11-14 years, and 15-18 years, respectively 4.