While keto and paleo diets offer compelling health benefits, they're fundamentally restrictive in ways that create measurable nutritional deficiencies. Unlike omnivorous whole-food diets, these eating patterns eliminate or dramatically reduce entire food categories that provide essential micronutrients. Understanding which supplements matter most can mean the difference between thriving on these diets and developing subtle deficiencies that undermine long-term health. Here's what the science and practical experience tell us about the supplements that genuinely matter.

Electrolytes: The Keto Imperative

For ketogenic dieters, electrolytes aren't optional—they're essential. When you dramatically restrict carbohydrates, your body shifts metabolically, causing rapid water and mineral loss during the adaptation phase. This creates what many call "keto flu," characterized by headaches, fatigue, and brain fog.

The three critical electrolytes are sodium, potassium, and magnesium. Most people instinctively add salt to their food, but potassium and magnesium require deliberate attention. Potassium is found in abundance in potatoes, beans, and fruits—all restricted on keto. Magnesium similarly comes predominantly from vegetables and whole grains. A typical keto dieter can be deficient in both minerals, leading to muscle cramps, irregular heartbeat, and persistent fatigue.

Supplementing with a well-formulated electrolyte product containing all three minerals, typically in powdered form for easy mixing, addresses this directly. The ideal formulation provides sodium (often 500-1000mg per serving), potassium (1000-2000mg), and magnesium (200-400mg), without added carbohydrates or sugars.

Paleo dieters experience less dramatic electrolyte loss but may still benefit from supplementation, particularly if they're active or live in hot climates.

Vitamin C: Ancestral Gap Analysis

Here's where evolutionary biology becomes practical nutrition: our hunter-gatherer ancestors consumed vitamin C in quantities that would shock modern nutritionists. They ate organ meats, bone marrow, and diverse wild plants—many of which are unavailable or unpalatable to modern consumers. More importantly, they consumed enormous amounts of vitamin C-rich plants: wild fruits, berries, leafy greens, and even tree bark when necessary.

Research suggests ancestral populations consumed 400-2000mg of vitamin C daily, compared to the modern recommended dietary allowance of just 90mg for men and 75mg for women. Both keto and paleo dieters typically consume fruit in moderation (or eliminate it entirely in strict keto), meaning vitamin C intake drops significantly below ancestral levels.

The consequences are subtle but real. Vitamin C is crucial for collagen synthesis, immune function, and antioxidant protection. Paleo practitioners advocating for "ancestral eating patterns" face a philosophical contradiction: they can't achieve ancestral nutrient profiles without ancestral food abundance and diversity, which no longer exists.

Supplementing with 500-1000mg daily of vitamin C makes physiological sense for both diets, particularly for those minimizing fruit intake. This bridges the gap between modern food reality and ancestral nutritional targets.

Polyphenols: The Diversity Problem

Polyphenols are plant compounds with powerful antioxidant and anti-inflammatory properties, found abundantly in colorful vegetables, fruits, berries, coffee, tea, and wine. These compounds are increasingly recognized as crucial for metabolic health, cardiovascular function, and longevity. The ancestral diet likely provided thousands of different polyphenols from diverse wild plants.

Both keto and paleo dieters face a polyphenol deficit. Keto eliminates or minimizes fruit and is often light on colorful vegetables. Paleo dieters do better, but the average paleo plate is less botanically diverse than what our ancestors consumed. We've lost the habit of eating wild greens, obscure berries, and seasonal plants that once provided polyphenol diversity.

The practical solution involves both food and supplementation. First, prioritizing colorful low-carb vegetables (leafy greens, cruciferous vegetables, bell peppers, berries where tolerated) increases polyphenol intake. Beyond that, targeted supplementation with polyphenol extracts—such as resveratrol, quercetin, or comprehensive polyphenol blends derived from grape seed, green tea, or berry sources—helps restore what's been lost.

Research increasingly suggests that polyphenol intake correlates with longevity and metabolic health, making this gap one of the more significant ones to address.

Magnesium: The Universal Deficiency

Magnesium deserves special attention because it's already deficient in most Western diets, and keto and paleo make it worse. This mineral is found primarily in leafy greens, seeds, nuts, and whole grains. Paleo dieters eliminate grains and may undereat seeds and nuts. Keto dieters, while potentially eating nuts, often don't eat enough leafy greens to meet magnesium needs.

The consequences are substantial. Magnesium is involved in over 300 enzymatic reactions in the body. Deficiency manifests as muscle cramps, sleep disruption, anxiety, and constipation—complaints commonly heard from people new to keto. A typical supplemental dose ranges from 200-400mg daily, though individual needs vary.

Notably, many electrolyte supplements include magnesium, so supplementing separately requires attention to total intake to avoid excessive dosing.

Calcium: Paleo's Primary Gap

Paleo dieters have a distinct calcium problem. By eliminating dairy—historically one of the most calcium-dense foods available—they need to source this mineral elsewhere. While small amounts come from leafy greens and fish with bones, most paleo dieters fall short of the recommended 1000-1200mg daily.

This matters more than some realize. Calcium isn't just about bones; it's involved in neuromuscular function, hormone regulation, and cardiovascular health. Long-term inadequacy can subtly undermine health in ways that take years to manifest.

Paleo practitioners have several options: eat more leafy greens and fish with edible bones, supplement with calcium citrate (which doesn't require stomach acid for absorption), or embrace the fact that some modern supplementation aligns with achieving ancestral nutrient profiles even if it doesn't fit the ancestral food pattern.

Omega-3 Fatty Acids: Balancing the Ratio

Both keto and paleo diets often feature significant fat intake, but the balance matters. Modern keto and paleo diets can be heavily weighted toward omega-6 rich foods (nuts, seed oils, grain-fed meat) while being relatively low in omega-3s. Our ancestors had far more balanced omega-3 to omega-6 ratios because they consumed wild fish, grass-fed meat, and diverse plant foods.

Fish oil supplementation (1000-3000mg daily of combined EPA and DHA) or algae-based omega-3s for plant-forward practitioners helps restore this balance. This isn't about reaching excessive omega-3 intake but correcting the ratio to something closer to what human physiology evolved to handle.

Iodine: An Overlooked Critical Mineral

Iodine is rarely discussed but genuinely important. This mineral, crucial for thyroid function, comes primarily from seafood, dairy, and iodized salt. Strict paleo dieters who avoid salt and eat limited seafood can become iodine deficient. Keto dieters do better if they use iodized salt, but many opt for sea salt or mineral salt without iodine fortification.

Iodine deficiency manifests as thyroid dysfunction, fatigue, and metabolic slowdown. A simple 150mcg supplement or ensuring adequate seafood intake addresses this directly.

Vitamin D: Everyone's Challenge

While not unique to keto and paleo, vitamin D deficiency is near-universal in modern life, affecting people across all diets. Neither keto nor paleo provides reliable dietary vitamin D except through fatty fish and egg yolks (which paleo includes but keto may limit). Most people benefit from supplementing 1000-4000 IU daily, with higher doses appropriate for those with limited sun exposure.

Optional Considerations: Digestive Support

Many people new to keto experience digestive changes—constipation is common, particularly early on. Paleo dieters sometimes struggle with inadequate fiber. While addressing this through food (adding more leafy greens, increasing water intake) is preferred, some people benefit from supplemental fiber or digestive enzymes designed to handle lower-carb, higher-fat foods.

The Supplement Strategy

Rather than supplementing indiscriminately, a thoughtful approach involves:

First, assessing individual needs. Someone eating substantial amounts of seafood, colorful vegetables, and sunny exposure has different needs than someone eating more monotonously or living in a northern climate.

Second, prioritizing based on risk. Electrolytes and magnesium for keto dieters, calcium for paleo dieters, and vitamin C and polyphenols for both should be considered foundational.

Third, filling remaining gaps through improved food choices before defaulting to supplementation. Eating a wider variety of colorful vegetables, prioritizing seafood, and consuming organ meats (if tolerated) can address many deficiencies through whole foods.

Fourth, periodically reassessing. As your diet evolves and you learn to include more diverse foods, some supplementation may become unnecessary.

The Ancestral Compromise

Here's the uncomfortable truth: you can't achieve a purely ancestral nutrient profile without ancestral food diversity. Our ancestors had access to hundreds of plant species we've never heard of, seasonal abundance we can't replicate, and nutrient-dense foods like nose-to-tail animal consumption that most modern practitioners avoid.

Rather than pretending supplements are unnatural, a more honest approach embraces them as necessary tools for bridging the gap between ancestral biology and modern food reality. You're not abandoning the spirit of paleo or keto by supplementing; you're acknowledging that these diets are inherently modern interpretations of historical eating patterns, and supplementation helps us achieve health outcomes that our ancestors achieved through food abundance and diversity we simply don't have access to anymore.

The most successful long-term practitioners of these diets aren't those who minimize supplementation out of principle—they're those who pragmatically identify their individual nutritional gaps and address them, whether through food or supplements, to sustain optimal health.