Vitamin B6, also known as pyridoxine, is a water-soluble nutrient that plays a role in various bodily processes. It is considered an essential nutrient, meaning the body cannot produce it and must obtain it from external sources. While naturally present in many foods, a common form found in supplements and fortified foods is synthetic B6. This form is widely used due to its stability and cost-effectiveness.
What is Synthetic Vitamin B6?
Synthetic Vitamin B6 is pyridoxine hydrochloride, a chemically manufactured form of the vitamin. This compound is a stable hydrochloride salt of pyridoxine, suitable for use in dietary supplements and for fortifying various food products. Its chemical structure is identical to the pyridoxine found in some natural food sources.
This manufactured form is widely adopted in the supplement industry because of its stability, which allows for a longer shelf life, and its lower production cost compared to extracting natural forms. When consumed, synthetic pyridoxine hydrochloride is converted by the body into its active coenzyme form, pyridoxal 5′-phosphate (PLP), mainly in the liver.
Contrasting Synthetic and Natural B6
Natural Vitamin B6 exists in several distinct forms, or “vitamers,” including pyridoxine, pyridoxal, and pyridoxamine, all found in different foods. These natural forms are converted in the body to the active coenzyme pyridoxal 5′-phosphate (PLP), which the body utilizes for over 140 enzyme reactions. Foods rich in natural B6 include poultry, fish, organ meats, potatoes, other starchy vegetables, and many fruits.
Synthetic pyridoxine hydrochloride also converts to PLP in the liver after absorption. The primary difference between natural and synthetic forms lies in their initial chemical structure as they enter the body. Some naturally occurring pyridoxine in plants can be found in glycosylated forms, which may exhibit reduced bioavailability compared to other forms.
Important Considerations for B6 Intake
Adhering to recommended daily allowances (RDAs) for Vitamin B6 is important for healthy bodily functions, whether from food or supplements. For adults aged 19-50, the RDA is 1.3 milligrams per day, increasing for pregnant or breastfeeding individuals. Men over 51 need 1.7 milligrams daily, while women over 51 need 1.5 milligrams. Most individuals in the United States obtain sufficient B6 from their diet through foods like poultry, fish, potatoes, and fortified cereals.
While synthetic B6 is generally safe within recommended doses, excessive intake from high-dose supplements can lead to adverse effects. The tolerable upper intake level (UL) for adults aged 19 and older is 100 milligrams daily, a level typically only reached through supplementation. Consuming 200 mg or more of synthetic B6 daily, especially over extended periods, has been linked to peripheral neuropathy, characterized by numbness, tingling, and burning sensations in the limbs. Other symptoms of excessive intake include painful skin lesions, sensitivity to sunlight, nausea, and heartburn. Consult a healthcare professional before taking high-dose B6 supplements to avoid potential neurological issues.