It has been said that eating enough of the right plant foods such as mushrooms, nori, spirulina, chlorella, and unwashed organic produce means that there will be no need to worry about becoming B12 deficient. However, there is no scientific basis/evidence to support this belief. Many studies have shown that anyone can have low levels, including vegetarians and vegans. It appears as if vegans who are not taking supplements have a higher risk for deficiency. Daily recommended intake is 2.4 mcg a day for adults, this amount goes up 0.2 mcg during pregnancy and again if breastfeeding. Lack of B12 can lead to anemia, infertility, bone and heart disease, and nervous system damage. The ability to absorb B12 decreases with age, as such the Institute of Medicine recommends everyone over the age of 51 considers fortified foods and/or a vitamin B12 supplement.
Very few foods naturally contain vitamin D, this may explain global reports of vitamin D deficiency among both vegans and omnivores. Vitamin D is important to many bodily processes such as mood, immune function, muscle recovery and memory. Daily recommendation varies per age and during pregnancy, and some studies suggest the current requirements are too low. Other than diet vitamin D can be made from sun exposure by spending at least 15 minutes per day in the sun while it is strong, which also exposes you to the possible negative effects of excess UV radiation. The best way to find out if you are deficient is to be tested, those that are unable to consume enough foods or spend time in the sun may want to consider taking a supplement.
Omega-3 fatty acids can be split into 2 categories: 1) essential omega-3 fatty acids, alpha-linolenic acid is the only one, meaning you can only get it from diet; and 2) long chain omega-3 fatty acids this includes EPA and DHA which are not considered essential as the body can make these from ALA. Long chains play structural roles in the brain and eyes, adequate levels are important to brain development and risk of inflammation, depression, breast cancer, and ADHD. Getting enough ALA should in theory maintain adequate EPA and DHA levels, but studies suggest the conversion from ALA to EPA may be as low as 5-10% and 2-5% for DHA. To add to this research shows that vegetarians and vegans have up to 50% lower blood and tissue concentrations of EPA and DHA.
Iodine is crucial for healthy thyroid function which helps to control metabolism. During pregnancy and early infancy deficiency can lead to irreversible intellectual disability, and hypothyroidism in adults. Studies suggest that vegans are at considerable risk for deficiency and have up to 50% lower blood levels than vegetarians. Those who do not eat iodized salt, seafood, seaweed, or dairy products several times per week may want to consider taking a supplement.
Iron is a very important nutrient that is needed to make new DNA and red blood cells, as well as to carry oxygen in the blood and for energy metabolism; too little can lead to anemia, fatigue, and decreased immune function. The amount you need varies with age, and pregnancy, the best way to determine whether a supplement is required is to get your hemoglobin and ferritin levels checked. Unnecessary intake can do more harm than good by damaging cells of blocking absorption of other minerals, and extremely high levels can cause convulsions, organ failure, coma, and in some cases can be fatal.
Calcium is needed for good bone and teeth health, and it plays a role in heart health, muscle function, and nerve signalling. The recommended daily intake is 1,000 mg a day for most adults which increases to 1,200 mg for those over the age of 50. Studies agree that most vegans do not get enough calcium, those getting less than 525 mg a day tend to have increased risk of bone fractures. A supplement may be best if you are not getting at least 525 mg of calcium a day.
Zinc is important to immune function, repair of body cells, and metabolism; insufficient levels can lead to diarrhea, delayed wound healing, hair loss, and developmental issues. Recommendations are 8-11 mg a day for adults which increases to 11-12 mg during pregnancy and again to 12-13 if breastfeeding. Few plant sources contain high amounts of zinc and absorption may be limited do to their phytate content. Studies suggest that vegetarians and vegans have lower zinc intake and lower blood levels of zinc.
A well planned vegan diet may be able to fulfill all of the nutritional needs, but certain requirements may be difficult to achieve via diet and fortified foods alone which is especially true for vitamin D, B12, and long chain omega-3 fatty acids. Vegans who are unable to meet their dietary requirements may want to consider taking a supplement after consulting with a healthcare provider to determine what is best for them.
