Introduction
The ketogenic diet — a high-fat, low-carbohydrate eating approach — is popular for weight management and stable energy. But drastically limiting carbohydrates creates specific nutrient deficiencies that need to be consciously addressed. This guide explains which deficiencies occur on keto and how to fill them with supplements.
Why Keto Creates Nutrient Deficiencies
Several important changes happen on a keto diet:
- Water and electrolyte loss: with low insulin levels, the kidneys excrete more sodium and water
- Restricting grains and fruits: reduces intake of B-vitamins, fibre, and some minerals
- Increased fat consumption: requires more bile and certain nutrients for digestion
This is completely normal and manageable — you just need to know what to supplement.
Essential Supplements on Keto
1. Electrolytes (Critical!)
This is the most important one — electrolyte deficiency is the main cause of "keto flu" (Bostock et al., 2020).
Sodium:
- Ketosis causes faster sodium excretion
- Add 1-2 tsp of sea salt to food per day
- Drink broth or salt water
Potassium:
- Potassium-rich keto foods: avocado, spinach, mushrooms
- Add potassium citrate supplement if needed
- Target: 3,500-4,700 mg per day (including food sources)
- Magnesium deficiency is very common on keto
- 200-400 mg of magnesium citrate or glycinate per day
- Supports normal muscle function and energy-yielding metabolism
2. MCT Oil
MCTs (medium-chain triglycerides) absorb quickly and the body uses them as an energy source.
- Why on keto: helps produce energy quickly in ketosis
- How: start with 1 tsp per day, gradually increase to 1-2 tbsp
- Note: too much at once may cause digestive issues
3. Omega-3 (Fish Oil)
On a keto diet, it's important to balance the omega-6 to omega-3 ratio, as increased fat intake may raise omega-6 consumption.
- Why: EPA and DHA contribute to the normal function of the heart
- Dose: at least 500 mg EPA + DHA per day
- When: with a meal
4. Vitamin D
Especially important in Estonia's climate. Keto doesn't directly affect vitamin D needs, but people on keto tend to be more conscious of their nutrition.
- Why: contributes to the maintenance of normal bones
- Dose: 25-50 mcg (1,000-2,000 IU) per day
- When: with breakfast (plenty of fat on keto!)
5. B-Complex Vitamins
Limiting grains on keto reduces B-vitamin intake from food.
- Why: contributes to normal energy-yielding metabolism and the reduction of tiredness and fatigue
- Especially important: B1 (thiamine), B5 (pantothenic acid), B7 (biotin)
- When: morning
6. Fibre
Keto restricts many fibre-rich food sources (grains, fruit, legumes).
- Why: fibre supports normal digestive function
- Keto sources: avocado, flaxseeds, chia seeds, vegetables
- If needed, add: psyllium husk (~5-10 g per day)
"Keto Flu" and Electrolytes
"Keto flu" is a common phenomenon in the first days to weeks of a keto diet. Symptoms — headache, fatigue, muscle cramps, irritability — are mostly linked to electrolyte loss.
Quick fix:
- Add sodium — salt food more, drink broth
- Take magnesium — 200-400 mg before bed
- Eat potassium-rich food — avocado, spinach
- Drink enough water — but not too much (this dilutes electrolytes)
Most people feel improvement within 24-48 hours after balancing electrolytes.
Practical Keto Supplement Plan
Morning:
- B-complex (with food)
- Vitamin D (fatty breakfast)
- MCT oil in coffee (start with a small amount)
During the day:
- Electrolytes in drinking water (sodium + potassium)
- Omega-3 with lunch
Evening:
- Magnesium (before bed)
- Fibre supplement (if needed)
Common Mistakes
- Ignoring electrolytes — this is the #1 keto mistake and the main cause of keto flu
- Adding only sodium — potassium and magnesium are equally important
- Too much MCT at once — digestive issues, start small
- Forgetting fibre — keto doesn't mean only fat and protein
- Drinking too much water without electrolytes — dilutes electrolytes and worsens the situation
Frequently Asked Questions
How long does keto flu last? Typically 3-7 days. Adding electrolytes can significantly reduce or even prevent symptoms.
Do I need to take all of these supplements? Electrolytes are mandatory on keto. The rest depend on your food choices and individual needs.
Do store-bought electrolyte drinks work? Most sports drinks contain sugar and too few electrolytes. Look for sugar-free electrolyte powders or make your own (water + salt + potassium chloride + lemon juice).
Is MCT oil necessary? Not mandatory, but a useful energy source for many, especially during the transition to ketosis.
Does keto have special needs that a regular multivitamin doesn't cover? Yes — mainly electrolytes (especially sodium), which multivitamins typically don't contain in sufficient amounts.
References
- Bostock, E.C.S. et al. (2020). Consumer reports of "keto flu" associated with the ketogenic diet. Frontiers in Nutrition, 7, 20.
- Paoli, A. et al. (2013). Beyond weight loss: a review of the therapeutic uses of very-low-carbohydrate (ketogenic) diets. European Journal of Clinical Nutrition, 67(8), 789-796.
- Harvey, C.J.D.C. et al. (2019). The use of nutritional supplements to induce ketosis and reduce symptoms associated with keto-induction: a narrative review. PeerJ, 7, e7749.
- Volek, J.S. & Phinney, S.D. (2012). The Art and Science of Low Carbohydrate Performance. Beyond Obesity LLC.
See also:
Browse our electrolyte selection at MaxFit.ee →
Disclaimer
A food supplement is not a substitute for a varied and balanced diet and a healthy lifestyle.
