New year… maybe a little more curious about you. Not a new you, not a whole life overhaul. Perhaps just the you who’s done with dragging through the day and wondering why feeling “off” has become your norm.

This isn’t about chasing perfection. It’s about tuning into what your body might be trying to tell you, and giving it the nutrients it needs to actually function (hello, energy, mood, focus, and sleep 😴).

Even if you’re eating a relatively balanced diet, it’s surprisingly easy to fall short on some of the key vitamins and minerals, also known as micronutrients, your body needs to function optimally. Between busy schedules, hormonal shifts, midlife metabolic changes, and a food system that doesn’t consistently deliver, small gaps in nutrition can turn into significant issues over time.

Fatigue, brain fog, mood swings, or that “blah” feeling? It’s not always menopause, and often, it’s fixable.

In this blog, we’re diving into five essential but often-overlooked micronutrients: iron, magnesium, calcium, vitamin B12, and vitamin D. When they’re off, you feel it. Let’s take a look at how they work, what signs to look for, and how to support your body with food and supplements  – only when needed (no TikTok trends required 😉).

🩸 Iron: For Energy, Focus, and Feeling Human Again

If you’ve ever stood up and felt like the room spun, reached for your third coffee by 10 a.m., or felt bone tired despite a solid night of sleep, iron could be the issue.

Iron helps your body make hemoglobin, the protein in red blood cells that carries oxygen throughout your body. When your red blood cells are healthy, oxygen flows smoothly to your muscles, brain, and organs, helping you feel energized, focused, and strong. When iron dips, everything from mood to energy to body temperature can take a hit. Cold hands and feet? Could be iron. (1)

Iron deficiency is super common, especially in women with heavy periods, during perimenopause and menopause, during pregnancy, or for anyone not consuming enough iron through food. And often, it doesn’t wave a red flag until it’s really low. (1)

An extensive study found that adults with heart disease and lower serum iron levels had a higher risk of complications and poorer outcomes, underscoring iron’s role in supporting overall resilience, particularly in chronic conditions. (2)

Top food sources: Lean meat and seafood are the richest dietary sources of heme iron; nuts, beans (lentils, lima beans), and vegetables (spinach, Swiss chard) are the richest dietary sources of nonheme iron, along with fortified cereals. Check out my previous blog for more iron sources, tips, and tricks!
Note: Pair iron-rich foods with vitamin C (such as citrus or tomatoes) to improve absorption, and use an iron skillet to increase absorption. (1)

💊 Don’t supplement unless your provider recommends it. Excessive iron intake can be harmful, so test first.

🧘‍♀️ Magnesium: For Stress, Sleep, and Staying Chill

Magnesium might just be the mineral of the moment, and for good reason. Magnesium supports more than 300 processes in your body, including how well you sleep, how you respond to stress, and even how your muscles recover after movement. (4)

If you’re waking up at 3 a.m., feeling wired but tired, snapping at that slow walker in the grocery store (no judgment), or dealing with chronic tension, magnesium may be part of the picture. (5)

Modern life depletes magnesium quickly, including stress, caffeine, alcohol, medications, and poor digestion. And here’s a bonus fact: your body also needs magnesium to activate vitamin D. So if your D levels are stubbornly low, magnesium might be missing from the equation. (4)

Food sources: leafy greens, nuts, seeds, whole grains, and yes—dark chocolate 🍫. (4)

If symptoms persist, the correct type of supplement might help. Think magnesium glycinate or threonate, not citrate, unless you’re looking for a bathroom sprint.🚽(4)

*Always check with your provider first.

🦴 Calcium: Yes, It’s About Bones, But Also So Much More

When we hear calcium, we tend to picture bones or milk mustaches 🥛, but it also helps your heart beat, your muscles contract, and your nerves send signals. If you’re not getting enough from food, your body pulls calcium from your bones, your built-in bank account, which weakens bone density over time. (7) Many of us are managing this absolute struggle!

During and after menopause, calcium requirements increase, whereas absorption declines. Pair that with low estrogen, and bone loss can occur quickly. (8,9) Let’s not wait for the surprise fracture to take action.

🥬Food sources: dairy, fortified plant milks, leafy greens, tofu, canned salmon or sardines with bones, fortified cereals or orange juice (check the labels!). (7)

✨ Spread calcium-rich foods throughout the day for better absorption.

💊 A supplement might help if food isn’t enough or you’ve been diagnosed with osteopenia or osteoporosis, but too much can interfere with other nutrients and impact digestion. Prioritize food, and supplement as directed by your healthcare provider. (7)

🧠 Vitamin B12: For Brainpower, Nerve Health, and Daily Energy

Vitamin B12 plays a critical role in nerve health, red blood cell production, and energy metabolism. So when it’s low, you feel it – fatigue, brain fog, low mood, and numbness or tingling in your hands or feet are all signs to watch for. (10,11)

Here’s a personal story: in my very first job as a dietitian, I reviewed a patient’s laboratory results before the doctor and identified an apparent B12 deficiency. They’d been struggling mentally for months, and all they needed was a simple supplement. It was eye-opening… and frustrating. One basic test could have made a big difference earlier.  So if your brain’s feeling off, don’t ignore it. Run the labs. It’s worth it.

Here’s the tricky part: B12 deficiency can creep in slowly, especially as we age. And it’s often mistaken for just getting older, menopause, orbeing busy and tired. (11) Sound familiar?

👀 Who’s at risk?
Adults over 50, anyone taking antacids or metformin, people with gut issues, vegetarians, and vegans. (11)

🍳Food sources: meat, fish, eggs, dairy, fortified plant milks, nutritional yeast. (11)

💊 Supplements come in tabs, sprays, drops, or injections, and many people do well with methylcobalamin (a more active, absorbable form). Since B12 is water-soluble, your body will flush out what it doesn’t need, making it generally safe to supplement under your provider’s guidance. (11)

☀️ Vitamin D: For Immunity, Mood, and Muscle Strength

The sunshine vitamin isn’t just about bones (though a super important role!). Vitamin D supports mood, muscle, and immune function, and calcium absorption; low levels are common, particularly in the winter months. (14,15)

Your body produces vitamin D when your skin is exposed to sunlight, but aging, darker skin, sunscreen, and spending a lot of time indoors can limit your natural production. And food alone doesn’t usually cut it. (14)

🌥️Signs you might be low: fatigue, frequent illness, mood dips, muscle aches, or not feeling like yourself. (14)

🥚Food sources: fatty fish (like salmon), egg yolks, and fortified plant milks. (15)
☀️Sunlight: 10-20 minutes of safe, direct sun on bare skin helps—but varies by location, skin tone, and time of year. (15)

💊 Most adults do well with 600-2,000 IU daily. Some may need more, depending on body weight, skin tone, and absorption issues. A blood test can help guide the correct dose, as personalized always beats guesswork. (14,15)

🧩 Putting It All Together

I know, it sounds a little overwhelming when I wanted to start the new year with simplicity here :0). You don’t need a supplement aisle overhaul, you just need a better snapshot of what your body might be missing.

And a quick note on supplements: they’re not regulated like medications, so what’s on the label isn’t always what’s in the bottle. Stick with third-party-tested brands, and always consult your provider before starting something new. (16)

Micronutrients like iron, magnesium, calcium, B12, and vitamin D may be small, but they pack a powerful punch. When even one is out of balance, your energy, mood, focus, or sleep can be affected. (1,4,5,7,10,11,14,15)

So if something feels off, don’t brush it off. Test when needed. Tweak your plate. Supplement smartly. And most importantly, listen to what your body’s been trying to tell you.

Need help figuring out what fits you best? I’m here for that. 💛 Book a Discovery Call Here!

Please note: This blog post is for informational purposes only and does not constitute medical advice. Always consult with a healthcare provider for personalized guidance.

References

1. Mayo Clinic. Iron deficiency anemia. Mayo Clinic. Published January 4, 2022. https://www.mayoclinic.org/diseases-conditions/iron-deficiency-anemia/symptoms-causes/syc-20355034
2. Lu, J., Ma, Z., Zhang, X., Zhong, W., Zou, Y., & Yuan, J. (2024). Association of serum iron with all-cause mortality and cardiovascular mortality in cardiovascular patients: a retrospective cohort study based on the NHANES 1999–2018. Frontiers in Cardiovascular Medicine, 11. https://doi.org/10.3389/fcvm.2024.1414792
3. McCann, S., Mason, L., Milosavljevic, B., Ebrima Mbye, Touray, E., Colley, A., Johnson, W., Lloyd-Fox, S., Elwell, C. E., & Moore, S. E. (2023). Iron status in early infancy is associated with trajectories of cognitive development through preschool age in rural Gambia. PLOS Global Public Health, 3(11), e0002531–e0002531. https://doi.org/10.1371/journal.pgph.0002531
4. Shmerling, R. H. (2025, June 3). What can magnesium do for you, and how much is required? – Harvard Health. Harvard Health. https://www.health.harvard.edu/blog/what-can-magnesium-do-for-you-and-how-much-do-you-need-202506033100
5. Cleveland Clinic. (2021). Electrolytes: Types, Purpose, and Normal Levels. Cleveland Clinic. https://my.clevelandclinic.org/health/diagnostics/21790-electrolytes
6. Wang, J., Xing, F., Sheng, N., & Xiang, Z. (2022). Associations of the Dietary Magnesium Intake and Magnesium Depletion Score With Osteoporosis Among American Adults: Data From the National Health and Nutrition Examination Survey. Frontiers in Nutrition, 9. https://doi.org/10.3389/fnut.2022.883264
7. Harvard T.H. Chan School of Public Health. (2023). Calcium. The Nutrition Source. https://nutritionsource.hsph.harvard.edu/calcium/
8. Hou, X., Hu, J., Liu, Z., Wang, E., Guo, Q., Zhang, Z., & Song, Z. (2023). L-shaped association of serum calcium with all-cause and CVD mortality in the US adults: A population-based prospective cohort study. Frontiers in Nutrition, 9, 1097488–1097488. https://doi.org/10.3389/fnut.2022.1097488
9. Bailey, R. L., Zou, P., Wallace, T. C., McCabe, G. P., Craig, B. A., Jun, S., Cauley, J. A., & Weaver, C. M. (2019). Calcium Supplement Use Is Associated With Less Bone Mineral Density Loss, But Does Not Lessen the Risk of Bone Fracture Across the Menopause Transition: Data From the Study of Women’s Health Across the Nation. JBMR Plus, 4(1), e10246. https://doi.org/10.1002/jbm4.10246
10. Harvard T.H. Chan School of Public Health. (2019, June 4). Vitamin B12. The Nutrition Source. https://nutritionsource.hsph.harvard.edu/vitamin-b12/
11. National Institutes of Health. (2024). Office of Dietary Supplements – Vitamin B12. Nih.gov; National Institutes of Health. https://ods.od.nih.gov/factsheets/VitaminB12-HealthProfessional/
12. Selinger, E., Kühn, T., Procházková, M., Anděl, M., & Gojda, J. (2019). Vitamin B12 Deficiency Is Prevalent Among Czech Vegans Who Do Not Use Vitamin B12 Supplements. Nutrients, 11(12), 3019. https://doi.org/10.3390/nu11123019
13. Vitamin B12 Deficiency Anemia Information | Mount Sinai – New York. (n.d.). Mount Sinai Health System. https://www.mountsinai.org/health-library/diseases-conditions/vitamin-b12-deficiency-anemia
14. Cleveland Clinic. (2022, August 2). Vitamin D deficiency: Causes, symptoms & treatment. Cleveland Clinic. https://my.clevelandclinic.org/health/diseases/15050-vitamin-d-vitamin-d-deficiency 
15. Vitamin D for the Prevention of Disease. (2024, June 3). Www.endocrine.org. https://www.endocrine.org/clinical-practice-guidelines/vitamin-d-for-prevention-of-disease
16. Food and Drug Administration. FDA 101: Dietary supplements. U.S. Food and Drug Administration. Published June 2, 2022. https://www.fda.gov/consumers/consumer-updates/fda-101-dietary-supplements