7 Nutrient Deficiencies Common in People Over 40

Philip Blackett
May 14
4 min read

A grandfather and his grandson dipping chocolate chip cookies in glasses of milk

After the age of 40, physiological changes like reduced nutrient absorption, hormonal shifts, and lifestyle factors increase the risk of specific nutrient deficiencies. These deficiencies often fly under the radar but contribute to fatigue, cognitive decline, bone loss, and chronic disease. Drawing on clinical research, this guide reveals the most common deficiencies in adults over 40 years old and science-backed strategies to address them.

1. Vitamin D

Why It’s Common: The skin’s ability to synthesize vitamin D declines by 10% per decade after 40 years old, while indoor lifestyles and sunscreen use further reduce sun exposure [6] [14].

Symptoms: Bone pain, frequent infections, depression, muscle weakness.

Fix It:

Supplements: 1,000 – 2,000 IU / day of D3 (with K2 for better absorption) [6].
Diet: Fatty fish (salmon, mackerel), fortified dairy / plant milks.
Sunlight: 10 – 15 minutes of midday sun daily (arms and / or legs exposed) [14].

2. Vitamin B12

Why It’s Common: Stomach acid production decreases with age, impairing B12 absorption. PPIs and metformin exacerbate this [7] [13].

Symptoms: Fatigue, numbness, memory issues, anemia.

Fix It:

Sublingual Supplements: 1,000 – 2,000 mcg / day bypass gut absorption issues [7].
Diet: Beef, eggs, nutritional yeast, fortified cereals.
Injections: For severe deficiency (per healthcare provider guidance).

3. Magnesium

Why It’s Common: Soil depletion and processed diets lead to inadequate intake. Stress and medications (diuretics) increase excretion [15] [8].

Symptoms: Muscle cramps, insomnia, anxiety, high blood pressure.

Fix It:

Supplements: 300 – 400 mg / day of magnesium glycinate or citrate [15].
Diet: Pumpkin seeds, spinach, almonds, dark chocolate.

4. Iron

Why It’s Common: Menstruating women remain at risk until menopause; chronic inflammation or digestive issues impair absorption [10] [14].

Symptoms: Pale skin, brittle nails, shortness of breath.

Fix It:

Heme Iron Sources: Red meat, oysters (better absorbed than plant-based iron).
Pair with Vitamin C: Add bell peppers or citrus to meals to boost absorption [14].
Avoid Tea / Coffee with Meals: Tannins inhibit iron uptake.

5. Calcium

Why It’s Common: Declining estrogen / testosterone accelerate bone loss. Many avoid dairy due to lactose intolerance [6] [13].

Symptoms: Frequent fractures, brittle nails, dental issues.

Fix It:

Non-Dairy Sources: Kale, fortified plant milks, sardines with bones.
Supplements: 500 – 600 mg / day (split doses for better absorption) [13].

6. Omega-3s

Why It’s Common: Low fish intake and high omega-6 consumption from processed foods create imbalance [11] [5].

Symptoms: Dry skin, joint pain, mood swings, poor focus.

Fix It:

Supplements: 1,000 – 2,000 mg / day of EPA / DHA from algae or fish / krill oil [11].
Diet: Walnuts, chia seeds, wild-caught salmon.

7. Folate (Vitamin B9)

Why It’s Common: Alcohol use, poor diet, and medications (methotrexate) deplete folate. Heat destroys it in cooked foods [9] [12].

Symptoms: Fatigue, mouth sores, poor immunity.

Fix It:

Supplements: 400 – 800 mcg / day of methylfolate (active form) [9].
Diet: Raw leafy greens, lentils, avocados.

Pro Tips for Nutrient Optimization

Test, Don’t Guess: Request blood tests for ferritin, B12, and 25(OH)D during annual checkups [7] [13].
Pair Nutrients: Take vitamin D with K2, iron with vitamin C, and magnesium with calcium for synergy.
Limit Antinutrients: Soak grains / legumes to reduce phytates that block mineral absorption [10].

When to See a Professional

Consult a healthcare provider if you experience:

Persistent fatigue despite dietary changes
Unexplained hair loss or neurological symptoms
Bone fractures without significant trauma

Thank you for reading. What is the ONE biggest takeaway from reading this article that you can now apply to your life today?

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