Why You Feel Tired After 35: 5 Nutrients You're Missing

Estimated Reading Time: 9 minutes

Published on: 11 Dec 2025

Celebrated your 35th birthday recently, but already feel like you're pushing 50?

That midday exhaustion, persistent pain after workouts, foggy brain, and waking up tired even after a full night's sleep!

You might have tagged it 'just aging'.

But what if it's not just getting older?

There's a high chance that your body is missing key nutrients it needs to keep up with the demands of aging. The results? Your energy, recovery, heart, and brain are all at risk.

"But I Eat Healthy!" Well, That's Not Always Enough

Most of us think, "If I eat healthy, I must be getting all the nutrients". However, that's the biggest myth of the generation.

Even a modern-day 'balanced' diet can fall short of essential nutrients. Here are the reasons why:

An 'ideal' balanced diet hugely depends on your age and health. A 35-year-old has different nutrition requirements than a 25-year-old. Harsh reality! But only a few people follow a customized diet plan.

Although aging is a natural process, it also affects your body's ability to absorb nutrients. Simply put, even if you eat healthy, your body can extract the best and maximum amount of essential nutrients.

Food processing and refining remove the nutrient-rich outer layers, thereby reducing the fiber, vitamins, and minerals in the final products.

Soil depletion and extensive farming practices have affected the nutrients in raw crops. Would you believe that spinach today has way less iron and magnesium than it did 50 years ago?

The modern-day lifestyle, stress, and processed food are burning magnesium and B12 faster.

Nowadays, people are obsessed with low-fat meals, which results in poor absorption of fat-soluble vitamins like A, D, E, and K. Even your granola bars and protein bars lack essential micronutrients.

Moreover, if you are someone who loves overcooked veggies recipes, you are definitely destroying heat-sensitive and water-sensitive nutrients like Vitamin B and C.

Vegans and vegetarians often miss B12, iron, and omega-3s. On the other hand, a non-vegetarian diet has less folate, creatine, and prebiotics.

And probably these are a few reasons why more than 92% of Americans have at least one vitamin or mineral deficiency even after eating "clean."

Eating clean and healthy is great. But it's not a guarantee you're getting everything your body needs, especially after 35.

How to Know You Are Running Low on Nutrients

Your body is probably way smarter than you think. If anything goes down, it signals you. Here are the signs that suggests your body's lacking essential nutrients:

You feel constantly tired, no matter how much you sleep.

Dry skin, brittle nails, thinning hair, and unexplained weight loss/weight gain.

Your body struggles with muscle cramps, twitches, and weird aches.

Brain fog, forgetfulness, and weaker immunity (you fall sick often).

You are cranky, moody, or anxious more often than usual.

Slow recovery after workouts and cellular healing, even after minor accidents.

If you're facing more than two of these signs, it's worth considering a blood test.

6 Key Nutrients Your Body Starts Lacking After 35

Let's be practical, everyone's body works a little differently. Two people, same age, different metabolism, totally different needs!

Maybe a 36-year-old man's feeling drained because he's low on geranylgeraniol (yes, that can mess with testosterone). Meanwhile, a perimenopausal woman in her 40s might be anxious or moody because of her hormonal shifts.

But even with those differences, there are a few key nutrients most adults start missing after 35. Here's the list of such six key nutrients.

Magnesium (Probably the reason for day-long tiredness)

Do you often struggle with fatigue, spasms, muscle cramps, and sleepless nights? This can be a sign of a magnesium deficiency.

Why Your Body Lacks Magnesium After 35

As you age, your body can't absorb sufficient magnesium from food sources.

Neither the kidneys can retain magnesium for a long time (aging often slows down the kidneys' retention ability).

Moreover, conditions like type 2 diabetes and medications like antacids and diuretics can also increase the risk of magnesium deficiency.

How Much Magnesium Do You Need?

After 30, women need 320 mg of magnesium per day, while adult men need a higher dose of 420 mg.

What to Do:

Increase your intake of magnesium-rich foods like spinach, kale, almonds, and whole grains.

Some mineral water and hydrogen water (based on magnesium tablets) can also provide your body with sufficient magnesium.

If diagnosed with extreme Mg deficiency, consider supplements like magnesium glycinate or malate (they are absorbed more easily in the gut).

CoQ10 (your personal cellular energy booster)

CoQ10 is a natural antioxidant that plays a crucial role in cellular energy production. What makes it more important? It supports heart, brain, and bone health. If muscle weakness and fatigue have become your new normal, your CoQ10 levels may be dropping with age.

Why Your Body Lacks CoQ10 After 35

That's a part of natural aging. Though your body makes CoQ10 on its own, its level significantly declines as you age.

If you have recently recovered from an accident or treatment, your cells might be using extra energy, resulting in CoQ10 decline.

Further, genetics or medications can also exhaust natural CoQ10 levels.

How Much CoQ10 Do You Need?

A healthy adult needs about 100-200 mg of CoQ10 per day. However, it might vary depending on the age and medical history.

What to Do:

Add more CoQ10-rich foods, including fatty fish, spinach, and broccoli.

Limit the consumption of acidic foods, such as meat, pasta, and cheese, to increase the bioavailability of CoQ10.

To reverse age-related CoQ10 deficiency, consider CoQ10 supplements (choose ubiquinol over ubiquinone for greater absorption).

If you are on drugs like statins, complement it with supplements like ubiquinol or geranylgeraniol, to support overall health.

Vitamin B12 (high chance if you're constantly forgetting things)

Struggling even to remember your essentials or catch a breath midday? You probably need to get your Vitamin B12 levels checked. Whether it's your nerve function, energy, or red blood cells, they all require Vitamin B12, which decreases as you age.

Why Your Body Lacks Vitamin B12 After 35

With aging, the ability to produce stomach acid declines, which is important for the absorption of Vitamin B12.

Plant-based eaters are especially prone to B12 deficiency, but even meat-eaters over 35 can struggle to absorb it

Certain gastrointestinal conditions and medications like metformin can also interfere with B12 absorption.

How Much Vitamin B12 Do You Need?

Generally, 2.4 micrograms (mcg) of vitamin B12 per day.

What to Do:

Meat-eaters should focus more on fish, poultry, and eggs.

Vegans or vegetarians must consider Vitamin B12 supplements or fortified foods like yeast and cereals.

For supplements, choose a more bioavailable form of B12, i.e., methylcobalamin.

Also Read: 23 Food Items High in Cholesterol: Pick What to Eat & Avoid

Iron (must for women, but not just for women)

Many think that iron is an essential nutrient only for women. However, even men need iron (though in lesser amounts). Iron is important for oxygen transportation, focus, strength, and muscle health. It even supports the formation of red blood cells. And guess what? Almost 1 in 3 adults in the US is running low on iron.

Why Your Body Lacks Iron After 35

The total iron need of the body increases with age, especially for pregnant women, mothers, menstruating women, and even for athletes (also the male ones).

With age, the body fails to absorb sufficient iron directly from the food sources.

Blood loss, whether from accidents or conditions such as ulcers or polyps, can decrease iron levels in the blood.

Certain medications, like blood thinners and proton-pump inhibitors (for acid reflux), can also increase the risk of iron deficiency.

How Much Iron Do You Need?

A healthy adult man needs 8 mg of iron per day. Adult women need 18 mg per day before menopause and 8 mg after. However, if you are pregnant, you may need a higher dose up to 27mg/day.

What to Do:

Add foods rich in iron, such as red meat, seafood, green vegetables, and legumes.

If depending solely on diet, please pair iron-rich food with Vitamin C for optimal absorption

Women (pregnant or menstruating) and athletes must consider iron supplements upon experts' recommendation.

Also Read: Men vs. Women: Do Diets Really Differ?

Vitamin D (severe can even lead to painful fractures)

Vitamin D, yes, the sun vitamin, is important. Your body uses it to absorb calcium, which strengthens bones and joints. Usually, even the short sun exposure is enough to produce all the vitamin D we need for the day. But with age, your body needs more than you can realize. And that's why adults often struggle with weaker bones.

Why Your Body Lacks Vitamin D After 35

The skin's ability to produce Vitamin D naturally from the sun declines with age.

If you are spending more time indoors or wearing sunscreen every time you step out.

There are only a few dietary sources of Vitamin D, making it challenging to obtain through meals.

How Much Vitamin D Do You Need?

Regardless of gender, adults must take 15 mcg (600 IU) of Vitamin D per day. This increases further to 20 mcg (800 IU) per day once you enter your 70s.

What to Do:

Consider cod-liver oil supplements.

If you follow an animal-based diet, focus on fatty fish, egg yolk, and beef liver.

Aim for at least 5-30 minutes of sun exposure a few times a week, particularly targeting the face, arms, and legs.

Omega-3s (will slowly make your skin dry)

Omega-3 fatty acids support mental clarity, skin glow, hormonal balance, and even prevent chronic inflammation. You might be surprised to find out that more than 80% of population doesn’t take sufficient Omega-3s.

Why Your Body Lacks Omega-3s After 35

An aging body becomes less efficient at converting omega-3 from plant-based sources.

Moreover, in developed nations, people do not consume enough omega-3 food sources.

Certain transitions, like pregnancy and breastfeeding, also increase the omega-3 requirement in females.

How Much Omega-3s Do You Need?

The ideal recommendation for omega-3s varies according to age, gender, and health status. However, in general, adults must take 1.1 to 1.6 grams of omega-3s (alpha-linolenic acid).

What to Do:

Increase your intake of omega-3-rich foods like fatty acids, nuts, seeds, eggs, soybeans, Brussels sprouts, etc.

Consider omega fatty-acid supplements like fish oil and krill oil.

Beyond the mentioned list, you must also consider antioxidant and anti-inflammatory foods in your diet to fight against the signs of aging.

Still Blaming Age for that Fatigue? Time to Wakeup

Maybe it's the nutrition. Your 30s and 40s aren't supposed to feel like you're constantly running on empty. Listen to your body, get regular check-ups, and discover what you're truly lacking. Eat smartly and start taking supplements (obviously after consulting your doctor). The more you care, the gracefully you age!

Disclaimer: The statements on this website have not been evaluated by the FDA. This product is not intended to diagnose, treat, cure, or prevent any disease.

References:

Macías Ruiz, M. V., et al. (2023). Magnesium in kidney function and disease: Implications for aging and sex. March 2023. Available: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10097335/

Barbagallo, M., et al. (2015). Magnesium and type 2 diabetes. January 2015. Available: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4549665/

Gröber, U., et al. (2019). Magnesium and drugs. May 2019. Available: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6539869/

de Barcelos, I. P., et al. (2019). CoQ10 and aging. May 2019. Available: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6627360/

Sayedali, E., et al. (2023). Association between metformin and vitamin B₁₂ deficiency in patients with type 2 diabetes. May 2023. Available: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10236989/

Office of Melbourne GI & Endoscopy. (2022). Iron deficiency. June 2022. Available: https://mgie.com.au/iron-deficiency/

Wu, Y. T., et al. (2023). Is use of a long‑term proton pump inhibitor or histamine‑2 receptor antagonist associated with iron‑deficiency anaemia? A Taiwan national case‑control study. Published 2025. Available: https://pubmed.ncbi.nlm.nih.gov/37756627/

Office of Dietary Supplements, NIH. (2022). Omega‑3 fatty acids – Health Professional Fact Sheet. July 2022. Available: https://ods.od.nih.gov/factsheets/Omega3FattyAcids-HealthProfessional/