Vitamin B12 and iron are two essential nutrients most people don't get enough of. With dietary choices limiting certain foods' consumption, especially for plant-based eaters, getting our fill of these two nutrients can quickly go out the window.
We start feeling tired, weak, and sluggish and wonder why. Are we not getting enough sleep? Are we stressed? Not eating well? As it turns out, it could be a nutrient deficiency causing your symptoms.
This article will cover the basics of vitamin B12 and iron, why they're essential, deficiency symptoms to watch for, and how to address low levels.
The Basics Of Iron And B12
Vitamin B12, also known as cobalamin, is a water-soluble vitamin that cannot be synthesized in the body. It's found in high concentrations in animal foods but can also be found in certain plant-based foods like nutritional yeast, mushrooms, and some algae.
Like all the B vitamins, B12 plays a vital role in energy production, but it's also essential for hematopoiesis (red blood cell formation), DNA synthesis, brain development, and nervous system function. It's also required as a co-factor for enzymes involved in fatty acid synthesis and myelin formation 1.
There's no denying that B12 plays a vital role in optimal performance, but here's why else you need it:
- Red blood cell production
- Bone health
- Energy production
- Heart health
- Hair, skin, and nail health
But there's a caveat with vitamin B12—absorption isn't as straightforward as entering the bloodstream, and everything is good. For B12 to be absorbed from the gut, it needs sufficient levels of a protein called intrinsic factor (IF), which is secreted by parietal cells of the stomach 2.
There are IF receptors in the gut that bind the complex of B12 and intrinsic factor and allow it to be absorbed. But if levels of intrinsic factor aren't sufficient, B12 can't be absorbed, and levels decline.
However, supplementing with sublingual B12—it skips the digestive tract—can help maintain levels even in the presence of low IF.
On the other hand, iron is an essential mineral that shares many common functions with B12. Its primary role is in oxygen transport, as iron is needed to form the heme component of hemoglobin, but it's also required for DNA production, brain health, red blood cell formation, immune function, and energy production 3.
Chronically low iron levels can cause iron-deficiency anemia, whereby the body produces microcytic (small, irregularly shaped) red blood cells and insufficient amounts of hemoglobin 4.
Because oxygen transport is limited, oxygen supply decreases, which means that cells, tissues, and organs don't receive enough oxygen to perform optimally. As a result, you'll see all the classic symptoms of iron deficiency like impaired cognition, weakened immunity, pregnancy complications, fatigue, and more.
For plant-based eaters who aren't consuming food sources of iron and vitamin B12, a deficiency can be a big thing. But you might be thinking, "I eat lots of veggies loaded with iron." While many plant foods contain iron, the difference is in the kind—heme vs. non-heme.
The former is inherent to animal foods and has high bioavailability, whereas the latter is found in plant foods and has a substantially lower absorption rate 5; you're looking at roughly 2-20% absorption for non-heme iron and 15-35% absorption of heme iron 6.
And several factors interfere with B12 absorption, too, so while you may think you're eating enough through diet, are you?
If you think you might be low in iron or B12, watch out for these symptoms:
- Extreme fatigue
- Pale skin
- Chest pain
- Racing heartbeat
- Shortness of breath
- Headache, dizziness, or lightheadedness
- Cold hands and feet
- Inflamed or painful tongue
- Brittle nails
- Cravings for non-nutritive substances (ice, dirt, etc.)
- Low appetite
Vitamin B12 deficiency
- Muscle weakness
- Numbness or tingling in hands or feet
- Difficulty walking
- Low appetite
- Weight loss
Much like their functions, several B12 and iron deficiency symptoms overlap, so it's important to get your levels tested if you suspect they might be low.
The other tricky thing with iron and B12 deficiencies is that excesses of other nutrients can mask their deficiency. For example, excessive folate intake can mask a B12 deficiency 7.
How To Boost Iron And B12 Levels
You can't argue that getting enough iron and B12 is imperative for optimal performance, but how do you get your levels up and avoid deficiency?
It's easy—diet combined with proper supplementation. Consuming a diet high in iron- and B12-rich foods is essential for maintaining normal levels, but supplementing to fill in the gaps is also crucial.
Load up your plate with these iron-rich foods:
- Red meat, pork, poultry
- Beans and legumes (lentils, white beans)
- Dark leafy green vegetables
- Dried fruit (apricots, raisins, etc.)
- Pumpkin seeds
Note that adding ascorbic acid (vitamin C) to iron-rich plant foods can help enhance non-heme iron absorption 8.
For B12, eat these foods:
- Nutritional yeast
- Organ meats
- Fish and seafood
- Milk and dairy
And when you're looking to fill in the gaps, reach for Performance Lab NutriGenesis® Multi—an ultra-modern multivitamin supplying 100% DV of 17+ essential vitamins and minerals complexed with cofactors to boost absorption and bioactivity.
Multi is designed to fill in nutritional gaps that may be missing from the diet and calibrated specifically to men's and women's needs.
And unlike other multivitamins, NutriGenesis® Multi contains no synthetic nutrient forms, isolated nutrients, additives, or fillers. It's ultra-clean foundational nutritional support for healthy whole-body biological performance.
- Ankar, A, Kumar, A. Vitamin B12 Deficiency. (Updated 2021 Jun 7). In: StatPearls (Internet). Treasure Island (FL): StatPearls Publishing; 2022 Jan-. Available from: https://www.ncbi.nlm.nih.gov/books/NBK441923/
- Lane DA, Millane TA, Lip GY. Psychological interventions for depression in adolescent and adult congenital heart disease. Cochrane Database Syst Rev. 2013;(10):CD004372.
- Abbaspour N, Hurrell R, Kelishadi R. Review on iron and its importance for human health. J Res Med Sci. 2014;19(2):164-174.
- Pawlak R, Berger J, Hines I. Iron Status of Vegetarian Adults: A Review of Literature. Am J Lifestyle Med. 2016;12(6):486-498.
- Hooda J, Shah A, Zhang L. Heme, an essential nutrient from dietary proteins, critically impacts diverse physiological and pathological processes. Nutrients. 2014;6(3):1080-1102.
- Monsen ER. Iron nutrition and absorption: dietary factors which impact iron bioavailability. J Am Diet Assoc. 1988;88(7):786-790.
- Cuskelly GJ, Mooney KM, Young IS. Folate and vitamin B12: friendly or enemy nutrients for the elderly. Proc Nutr Soc. 2007;66(4):548-558.
- Lynch SR, Cook JD. Interaction of vitamin C and iron. Ann N Y Acad Sci. 1980;355:32-44.