Vitamin B6, also known as pyridoxine, is a water-soluble essential nutrient found naturally in many foods and added to others. This vitamin plays a role in numerous bodily functions, including metabolism, brain development, and immune system health. Given its diverse functions, vitamin B6 is a common topic of discussion regarding its potential to help alleviate nausea.
How Vitamin B6 Addresses Nausea
Vitamin B6 may help alleviate nausea by influencing the production of specific brain chemicals called neurotransmitters. Its active form, pyridoxal 5′-phosphate (PLP), acts as a coenzyme in the synthesis of neurotransmitters such as serotonin and dopamine. These neurotransmitters regulate signals to the brain’s vomiting center. By helping to balance these chemical signals, vitamin B6 can potentially calm the communication that triggers feelings of queasiness.
The primary type of nausea for which vitamin B6 is most commonly recommended and studied is pregnancy-related nausea and vomiting. This condition can occur at any time of day and affects a significant number of pregnant individuals, particularly in the first trimester. While the exact mechanisms are not fully understood, hormonal changes during pregnancy are thought to disrupt neurotransmitter balance, and vitamin B6 supplementation may help restore this balance.
Beyond pregnancy-related nausea, vitamin B6’s role in neurotransmitter synthesis suggests potential for other general types of nausea, such as those caused by medication side effects. While less extensively studied for conditions like motion sickness or chemotherapy-induced nausea, its influence suggests a broader potential impact on nausea. However, evidence supporting its effectiveness for these other types of nausea is not as robust as for pregnancy-related nausea.
Practical Guidance for Taking B6
When considering vitamin B6 for nausea, it is recommended to take it regularly throughout the day to maintain consistent levels. For pregnancy-related nausea, common advice includes taking divided doses, such as 10-25 mg three or four times daily. This approach can help manage symptoms consistently, rather than waiting for nausea to become severe. Taking a dose proactively, such as before getting out of bed in the morning, is also beneficial for morning sickness.
Typical dosage recommendations for pregnancy-related nausea range from 30-75 mg per day. Up to 75-100 mg per day may be suggested for persistent symptoms, but it is important to consult a healthcare provider for personalized guidance. For general nausea in non-pregnant adults, a daily dose of 50 mg is suggested. Pyridoxine hydrochloride is the most common form of vitamin B6 found in supplements, available in various oral forms like capsules, tablets, and liquids.
Vitamin B6 can be taken alone or combined with doxylamine, an antihistamine available over-the-counter. This combination is a recommended first-line treatment for nausea and vomiting in pregnancy. If vitamin B6 alone does not provide sufficient relief, healthcare providers may suggest adding doxylamine.
Important Safety Information and Precautions
While generally considered safe at recommended dosages, excessive intake of vitamin B6 can lead to adverse effects. High doses, typically 500 mg or more daily over prolonged periods, have been associated with sensory neuropathy, a type of nerve damage causing tingling, numbness, and weakness, particularly in the hands and feet. This nerve damage can be progressive, and while symptoms often improve upon discontinuing the supplement, they may become permanent in some cases.
Other potential side effects of high vitamin B6 intakes include painful skin lesions, photosensitivity, and gastrointestinal symptoms like nausea and heartburn. The maximum allowable daily limit for vitamin B6 in supplements is 100 mg per day to avoid the risk of neuropathy. However, reports suggest neuropathy can occur at doses less than 50 mg, especially when taking multiple products containing vitamin B6.
It is important to consult a healthcare provider before starting vitamin B6 supplements, especially if pregnant, have pre-existing medical conditions, or are taking other medications. Vitamin B6 can interact with certain drugs, such as seizure medications (e.g., phenytoin, phenobarbital), potentially reducing their effectiveness. It can also interact with Parkinson’s disease medications like levodopa.