Nutrition & Lifestyle Medicine
Evidence-based information on nutrients, dietary patterns, and exercise for optimal health and disease prevention.
🥗 Key Nutrients
Vitamin A
Vision, immune function, skin health.
Sources: Carrots, sweet potatoes, spinach, liver, egg yolks
Deficiency: Night blindness, dry eyes, increased infection risk.
Excess: Toxicity with excessive supplementation; headache, nausea, bone loss.
RDA: 700–900 mcg/day (adults)
Vitamin B12
DNA synthesis, nerve function, red blood cell formation.
Sources: Meat, fish, dairy, eggs, fortified cereals, nutritional yeast
Deficiency: Anemia, neuropathy (nerve damage), cognitive decline, especially in vegans/vegetarians.
Excess: No toxicity from food; excess is excreted.
RDA: 2.4 mcg/day (adults)
Vitamin C
Collagen synthesis, immune support, antioxidant.
Sources: Citrus, berries, peppers, tomatoes, kiwi, broccoli
Deficiency: Scurvy (gum disease, poor wound healing), weakened immunity.
Excess: Kidney stones in susceptible individuals; diarrhea.
RDA: 75–90 mg/day (adults)
Vitamin D
Calcium absorption, bone health, immune regulation.
Sources: Fatty fish, egg yolks, mushrooms (sun-exposed), fortified milk
Deficiency: Soft bones (rickets in children, osteomalacia in adults), muscle weakness.
Excess: Hypercalcemia (high blood calcium), kidney damage with very high supplementation.
RDA: 600–800 IU/day; higher for older adults or limited sun exposure
Vitamin E
Antioxidant, protects cells from damage.
Sources: Nuts, seeds, vegetable oils, leafy greens, avocado
Deficiency: Rare; can cause neurological problems with severe malabsorption.
Excess: Excessive supplementation may increase bleeding risk.
RDA: 15 mg/day (adults)
Vitamin K
Blood clotting, bone mineralization.
Sources: Leafy greens, broccoli, Brussels sprouts, cabbage
Deficiency: Easy bruising, bleeding, bone loss.
Excess: No toxicity from food; high supplementation may interfere with blood thinners.
RDA: 90–120 mcg/day (adults)
Calcium
Bone health, muscle contraction, nerve signaling.
Sources: Dairy, leafy greens, fortified plant milks, almonds, sardines
Deficiency: Osteoporosis, weak teeth, muscle cramps, paresthesia (tingling).
Excess: Kidney stones, impaired iron/zinc absorption.
RDA: 1000–1200 mg/day (adults)
Iron
Oxygen transport, energy metabolism.
Sources: Red meat, poultry, fish, beans, fortified cereals, dark leafy greens
Deficiency: Anemia, fatigue, shortness of breath, impaired cognition.
Excess: Hemochromatosis (iron overload), organ damage; rare from food alone.
RDA: 8–18 mg/day (adults, higher for menstruating women)
Magnesium
Muscle and nerve function, energy production, bone health.
Sources: Nuts, seeds, whole grains, leafy greens, legumes
Deficiency: Muscle cramps, fatigue, irregular heartbeat, poor sleep.
Excess: Diarrhea, muscle weakness (rare from food).
RDA: 310–420 mg/day (adults)
Zinc
Immune function, wound healing, protein synthesis.
Sources: Oysters, beef, chicken, legumes, seeds, nuts
Deficiency: Weakened immunity, slow wound healing, hair loss, diarrhea.
Excess: Nausea, copper malabsorption, neurological effects with chronic excess.
RDA: 8–11 mg/day (adults)
Potassium
Blood pressure regulation, heart function, muscle contraction.
Sources: Bananas, avocado, sweet potatoes, spinach, beans, salmon
Deficiency: Low BP, fatigue, muscle weakness, irregular heartbeat (arrhythmia).
Excess: Hyperkalemia (high blood potassium), dangerous for those with kidney disease.
RDA: 2600–3400 mg/day (adults)
Omega-3 Fatty Acids
Heart health, brain function, inflammation regulation.
Sources: Fatty fish (salmon, mackerel), flaxseeds, chia seeds, walnuts
Deficiency: Increased heart disease and depression risk.
Excess: Increased bleeding risk, potentially increased prostate cancer risk.
RDA: 1.1–1.6 g/day (ALA); EPA+DHA unclear but 200–300 mg/day suggested
Fiber
Digestive health, blood sugar control, cholesterol reduction.
Sources: Whole grains, beans, vegetables, fruits, nuts, seeds
Deficiency: Constipation, elevated cholesterol, poor blood sugar control.
Excess: Bloating, cramping, gas (usually from rapid increase).
RDA: 25–38 g/day (adults)
Protein
Muscle maintenance, enzyme production, immune function.
Sources: Meat, fish, eggs, dairy, legumes, nuts, seeds
Deficiency: Muscle loss, weak immune function, slow wound healing.
Excess: No toxicity, but high intake stresses kidneys in those with disease.
RDA: 0.8 g/kg body weight (adults); higher for athletes/older adults
RDA = Recommended Dietary Allowance (U.S. standard). Needs vary by age, sex, health status, and pregnancy/lactation.
🍽️ Dietary Patterns
Mediterranean
Emphasizes olive oil, fish, whole grains, legumes, fruits, vegetables, and moderate wine. Low in red meat. Origins in coastal Mediterranean countries.
Evidence: Strong evidence for reduced heart disease, stroke, and all-cause mortality. Benefits cognition and may reduce Alzheimer's risk.
Best for: Heart health, weight management, disease prevention. Suits most people.
DASH (Dietary Approaches to Stop Hypertension)
High in fruits, vegetables, whole grains, lean protein, and low-fat dairy. Low in sodium, saturated fat, and added sugar.
Evidence: Proven to lower blood pressure and cholesterol. Reduces heart disease and stroke risk.
Best for: High blood pressure, heart disease prevention, weight loss.
Plant-Based / Vegan
Eliminates or minimizes animal products. Emphasizes vegetables, fruits, grains, legumes, nuts, seeds. Vegan is entirely plant-based.
Evidence: Associated with lower BP, cholesterol, and heart disease risk. Requires B12 supplementation; attention to iron, zinc, calcium.
Best for: Ethical concerns, environmental impact, health. Needs planning to ensure adequate nutrients.
Low-Carb / Ketogenic
Restricts carbohydrates (typically <50 g/day for keto) and emphasizes fat and protein. Induces ketosis.
Evidence: Effective for short-term weight loss and blood sugar control in diabetes. Long-term safety/sustainability debated. Not suitable for those with certain kidney/liver disease.
Best for: Type 2 diabetes management, rapid weight loss. May not be sustainable long-term.
Intermittent Fasting
Eating within specific time windows (e.g., 16:8: fasting 16 hours, eating within 8 hours). No food-type restriction, just when to eat.
Evidence: May promote weight loss and metabolic health. Results comparable to calorie restriction. Not ideal during pregnancy, for some athletes, or those with eating disorder history.
Best for: Weight management, simplifying eating patterns. Requires patience and suitability assessment.
💡 No single diet is "perfect". The best diet is one you can sustain long-term, enjoy, and that fits your health goals, values, and lifestyle. Work with a registered dietitian for personalization.
💪 Exercise & Movement
Aerobic / Cardio
Sustained, rhythmic activity elevating heart rate. Examples: running, cycling, swimming, dancing, brisk walking.
Examples: Running, cycling, swimming, elliptical, dancing, brisk walking
Frequency: 150 min moderate or 75 min vigorous per week (or equivalent).
Benefits: Stronger heart and lungs, better circulation, weight management, reduced heart disease/diabetes risk.
Resistance / Strength
Lifting weights or using bodyweight to build muscle. Examples: weightlifting, resistance bands, push-ups, squats.
Examples: Weightlifting, resistance bands, push-ups, bodyweight exercises, leg press
Frequency: 2+ days per week, targeting major muscle groups.
Benefits: Stronger muscles, denser bones, better metabolism, improved daily function, enhanced balance.
Flexibility / Stretching
Gently moving joints through their range of motion. Examples: yoga, tai chi, static stretching.
Examples: Yoga, tai chi, pilates, static stretching, foam rolling
Frequency: Daily or most days.
Benefits: Improved range of motion, reduced injury risk, better posture, stress relief.
Exercise as Medicine
Exercise is a powerful tool for preventing and managing chronic diseases:
• Heart disease: Aerobic exercise reduces risk by ~30%. Protects blood vessels, improves BP and cholesterol.
• Type 2 Diabetes: Exercise improves insulin sensitivity. Combined with weight loss, can achieve remission.
• Depression & Anxiety: Regular exercise is as effective as some antidepressants. Boosts mood, reduces stress.
• Osteoporosis: Weight-bearing and resistance exercise strengthens bones. Critical in older adults.
• Cancer: Regular activity reduces risk of several cancers and improves outcomes for survivors.
• Cognitive Decline: Aerobic exercise and strength training protect brain health and may reduce Alzheimer's risk.
Start where you are. Any movement is better than none. Consistency matters more than intensity.
🎯 Key Principles
Balance
A mix of nutrients from various food groups supports health. No single food is "perfect".
Whole Foods
Emphasize minimally processed foods—vegetables, fruits, whole grains, legumes, nuts, and lean proteins.
Consistency
Small, sustainable changes beat drastic diets. Long-term habits matter more than perfection.
Personalization
Genetics, health conditions, medications, preferences, and culture all affect optimal nutrition. Work with professionals.
Hydration
Water is essential. Aim for ~8 glasses daily; more if active or in hot climates.
Moderation
Portion control matters. Even healthy foods can contribute to weight gain in excess.
👨⚕️ Consult a Dietitian: For personalized nutrition advice, especially if you have chronic diseases (diabetes, hypertension, kidney disease) or are considering major dietary changes. Registered Dietitian Nutritionists (RDN) are certified specialists.
ℹ️ This information is educational and not a substitute for professional medical or nutritional advice.