Vitamin B1 (thiamine) recommended daily intake
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Recommended Daily Intake of Vitamin B1 (Thiamine) for Adults
The recommended daily intake (RDI) of vitamin B1 (thiamine) for adults is generally set at 1.2 mg per day for men and 1.1 mg per day for women over the age of 18. Pregnant women are advised to increase their intake to 1.4 mg per day to meet additional physiological needs 12. These recommendations are widely accepted and are based on maintaining normal blood levels and preventing deficiency symptoms.
Thiamine Intake Recommendations for Children and Special Populations
For children, the recommended intake is lower and increases with age, starting from 0.2 mg per day in early infancy. The requirement rises steadily as children grow older . Pregnant and lactating women have higher thiamine needs, as shown by biochemical markers, and should ensure increased intake 13. Elderly individuals may also have impaired thiamine utilization, suggesting a need for careful monitoring of their intake .
Thiamine Needs Relative to Calorie and Carbohydrate Intake
Thiamine requirements are closely linked to energy and carbohydrate consumption. A common guideline is to consume about 0.4 mg of thiamine for every 1,000 kilocalories (kcal) of energy intake . Clinical signs of deficiency have been observed at intakes below 0.5 mg per day, and studies suggest that normal enzyme activity and thiamine excretion are achieved at intakes of 0.07–0.08 mg per megajoule (MJ) of energy 34.
Thiamine Deficiency and Modern Diets
Despite the relatively low RDI, thiamine deficiency is still observed in various populations, sometimes affecting 20% to over 90% of certain groups, depending on the study . This suggests that the current RDI may not always be sufficient, especially in the context of modern diets and lifestyles that can increase thiamine depletion . Deficiency is more likely in people with chronic alcohol use, persistent vomiting, or after certain surgeries, but mild deficiency can also be present in the general population .
Food Sources and Intake Patterns
Thiamine is found in moderate amounts in many foods, with the richest sources being whole grains, brown rice, pork, poultry, soybeans, nuts, dried beans, peas, and fortified grain products like cereals . In some populations, such as Egyptians, the average daily intake is about 1.0 mg, with most thiamine coming from bread and cereal products . Processed foods can also contribute to thiamine intake, but reliance on these may not always provide optimal nutrition .
Safety and Upper Intake Levels
There is currently no established safe upper intake level for thiamine due to a lack of data on toxicity from high intakes . Thiamine is water-soluble and excess amounts are typically excreted, making toxicity rare.
Conclusion
The recommended daily intake of vitamin B1 (thiamine) is 1.2 mg for adult men and 1.1 mg for adult women, with higher needs during pregnancy and lactation. Requirements are influenced by energy and carbohydrate intake, and deficiency can occur even in populations with access to a variety of foods. Ensuring adequate thiamine intake is important for energy metabolism and overall health, especially in vulnerable groups and those with increased physiological needs 1234.
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