Vitamins 101: What They Do & How to Get Enough
When it comes to health, we tend to focus on protein, carbs, and fats — but the real magic often comes from vitamins. These tiny compounds don’t give us energy directly, but without them, we cannot release energy, build collagen, support immunity, or maintain strong bones and healthy blood.
And here’s the good news: most people can meet their vitamin needs through a varied, balanced diet, no complicated supplements required.
1. Fat-Soluble vs Water-Soluble Vitamins: Why It Matters
Vitamins fall into two groups:
Fat-soluble (A, D, E, K):
Absorbed with dietary fats
Stored in liver & fat tissue
Don’t need to be consumed daily
Higher risk of toxicity from supplements
Water-soluble (B vitamins + Vitamin C):
Absorbed directly into the bloodstream
Not stored (except B12)
Excess is excreted in urine
Need regular intake
Toxicity is rare but still possible with high-dose supplements
2. Fat-Soluble Vitamins: What They Do & What Lack Looks Like
Vitamin A
Roles: Vision (especially night vision), immunity, skin & mucous membranes, cell growth
Deficiency: Night blindness, dry eyes/skin, weakened immunity
Excess: Headaches, liver damage, birth defects
Sources: Carrots, sweet potatoes, leafy greens, liver, eggs, fatty fish
✨ Did you know? Eating too many carrots can tint your hands/face orange because beta-carotene gets stored in fat cells.
Your eyes need vitamin A (retinal) to detect low light, deficiency first shows up as night blindness.
Vitamin D
Roles: Bone health, calcium absorption, immune function, cell growth
Deficiency: Bone weakness, rickets (children), increased risk of falls/infections
Excess: High blood calcium → organ damage
Sources: Sunlight, eggs, fortified dairy/plant milk, salmon, mushrooms
✨ Did you know? Vitamin D begins as a cholesterol molecule in your skin - sunlight triggers the reaction that converts it.
Low magnesium can block vitamin D activation. Pair your vitamin D with magnesium-rich foods: Pumpkin seeds, leafy greens, dark chocolate, legumes.
Vitamin E
Roles: Powerful antioxidant, protects cell membranes, supports immunity
Deficiency: Rare, but can cause nerve issues, anemia
Excess: May increase risk of bleeding
Sources: Nuts, seeds, avocados, spinach, sunflower oil
✨ Did you know? A huge clinical trial (HOPE) showed vitamin E supplements do NOT reduce heart disease, despite decades of hype.
Vitamin K
Roles: Blood clotting, bone health
Deficiency: Rare (gut bacteria produce K2), newborns at risk
Excess: Natural K is safe; synthetic forms may cause liver issues
Sources: Leafy greens (spinach, kale), broccoli, asparagus
✨ Did you know? Your gut bacteria produce vitamin K2 - one reason adults almost never become deficient.
3. Water-Soluble Vitamins: The Energy & Repair Crew
Vitamin C
Roles: Collagen formation, antioxidant, wound healing, iron absorption
Deficiency: Scurvy, fatigue, gum bleeding, poor wound healing
Excess: Diarrhea, nausea, kidney stones (high doses)
Sources: Citrus, strawberries, peppers, broccoli, tomatoes, kiwi
✨ Did you know? Vitamin C “activates” iron by changing its electrical charge, it boosts iron absorption - a step also required to build collagen. Best combos to boost iron absorption: Spinach + lemon, lentils + peppers, oats + berries, meat + citrus.
It doesn’t prevent colds or flu, but it may help you recover slightly faster.
The B-Vitamin Family
B1, B2, B3, B5, B7 – Energy Release
Allow us to convert food → ATP (energy).
Deficiencies can show up as: fatigue, poor concentration, cracked lips, skin issues.
B6 – Amino Acid & Brain Support
Helps make hemoglobin & neurotransmitters.
Deficiency: skin issues, low energy, nerve problems.
B9 (Folate) – Cell Division
Vital in pregnancy and red blood cell formation.
Deficiency: anemia, fatigue.
B12 – Nerve & Blood Health (special case)
Stored in the liver; relies on stomach acid for absorption.
Deficiency: anemia, numbness, memory problems, fatigue.
Higher risk: vegans, older adults, those on antacid medication
Best B-vitamin sources: Whole grains, legumes, eggs, nuts, seeds, leafy greens, dairy, meat, seafood.
✨ Did you know?
Without B vitamins, your body can’t run the Krebs cycle — meaning you can’t produce ATP (energy).
Low B12 can make folate look “low” on blood tests — because B12 is needed to activate folate.
B12 is the only water-soluble vitamin your body can store for years, which is why deficiencies appear slowly.
4. How the Body Absorbs Vitamins
Fat-soluble vitamins require bile + fat, travel through the lymph system, and are stored. You can’t absorb vitamins A, D, E and K without fat. A fat-free salad = barely absorbing these fat-soluble vitamins. Consider adding healthy fats to your salads and cooked foods: olive oil, tahini, avocado, nuts, seeds.
Water-soluble vitamins move easily into the bloodstream and are not stored (except B12).
Overcooking veggies can destroy some water-soluble vitamins — steaming or quick sautéing helps preserve them.
5. The Easiest Way to Meet Your Vitamin Needs
A whole-food, varied diet covers everything:
Fruits: Vitamin C, A, B6, folate, biotin
Vegetables: A, C, K, E + most B vitamins
Healthy fats (nuts, seeds, oils): Vitamin E + help absorb A, D, E, K
Whole grains: B1, B3, B5, B7
Healthy proteins (fish, legumes, eggs, poultry): B vitamins, A, D, E
Supplements can be useful when truly needed, but food-first remains the gold standard.
Vitamins are small but mighty. They help us turn food into energy, repair tissues, protect cells from damage, build blood, support immunity, and keep bones strong. The simplest, most sustainable way to cover your needs? at a colourful, varied plate and let food do the work.
Want personalised support with your nutrition, weight loss or weight gain journey?
Reach out at coaching@zeevibe.com or fill out my contact form to start today. We’ll build long-lasting habits, not yo-yo diets. No restriction, no extremes - just sustainable, healthy eating patterns that stay with you for life.
With love,
Zeynep
References:
National Institutes of Health (NIH), Office of Dietary Supplements. Fact Sheets on Vitamins A, D, E, K, C & B Vitamins (2018–2023).
Harvard T.H. Chan School of Public Health – The Nutrition Source. Vitamin Guides (2019).
Sizer, F. & Whitney, E. Nutrition: Concepts and Controversies. (2017).
World Health Organization (WHO). Vitamin A & Vitamin D Deficiency Reports (2019).
Yusuf, S. et al. “Effects of Vitamin E Supplementation on Cardiovascular Outcomes.” New England Journal of Medicine. (2000, HOPE Trial).
Lobo, V., et al. “Free Radicals, Antioxidants and Functional Foods.” Pharmacognosy Reviews. (2010).
Wacker, M., & Holick, M.F. “Sunlight and Vitamin D: A Global Perspective.” Dermato-Endocrinology. (2013).
Shane, B. “Folate & Vitamin B12 Metabolism.” Annual Review of Nutrition. (2008).
University of Michigan (2015). B Vitamins Fact Sheet.
Hemilä, H., & Chalker, E. (2013). Vitamin C for the Common Cold. Cochrane Review.