7 Signs You’re Deficient in Vitamin D

Do you get enough Vitamin D? Luckily we seem to be coming out of the sun-fearing era slightly, but even so, with so many of us in office jobs, it can be really hard to get enough vitamin D.

Whilst some foods are fortified with vitamin D, they aren't natural whole foods-and even so, the amount they provide is tiny compared to the levels you can get naturally, from the sun.

There’s no substitute for getting regular blood tests to find out exactly where your vitamin D levels are sitting, but did you know certain symptoms may indicate a deficiency?

How’s your mood?

Sunlight boosts serotonin levels, which are associated with our mood. If you’re feeling inexplicably blue, vitamin D is definitely worth investigating.

You have darker skin

The darker your skin, the more sun exposure you’ll need to get sufficient vitamin D levels.  This means if you have darker skin and live further from the equator – or spend a lot of time indoors, you’re more likely to be deficient

You’re in pain

If you have bone or muscle pain, this could also point to low vitamin D levels. In fact, most muscle weakness appears to be linked to low levels of vitamin D.

You’re tired

If you’re generally feeling fatigued, this could be because you don’t have enough of the vitamin D required for its role in energy production.

Respiratory issues

Another potential symptom is chronic respiratory problems such as asthma – it’s been observed that higher vitamin D levels can decrease the severity of asthma attacks.

You’re overweight

Being overweight means you need move vitamin D in your system, since its fat soluble – whilst decreased levels also make it harder to lose weight.

You get every infection and bug going around

Vitamin D plays an important role in your immune system – so if you’re catching one thing after another, get those levels checked!

Getting Vitamin D Naturally: Smart Sun Exposure

The best and most efficient way to get vitamin D is through direct sun exposure on bare skin. But how much is enough? That depends on a few factors — your skin tone, location, time of year, and how much skin you expose. In Australia, spending around 10 to 20 minutes in the sun between 10am and 3pm (depending on the season and your location) can be sufficient for many people. However, in winter months or for those living in the southern states, more time may be needed to maintain adequate levels.

It’s important to find a balance between safe sun exposure and avoiding overexposure. Brief, frequent periods in the sun are generally safer and more beneficial than occasional long sunbathing sessions. Aim to expose areas like your arms, legs, or back without sunscreen for a short time, then apply protection if you're going to be outdoors longer.

Why Supplementation May Be Necessary

For many of us, especially those working indoors, living in urban environments or with darker skin tones, regular sun exposure isn’t always possible. In these cases, vitamin D supplements can be a useful tool. Cholecalciferol (vitamin D3) is the most effective form for supplementation, and it’s often recommended to take it with a fat-containing meal to improve absorption, as it’s a fat-soluble vitamin.

The dosage varies depending on your current levels, but many health practitioners suggest 1000 to 5000 IU per day as a general maintenance dose for adults. However, a blood test is the only way to know your baseline and the correct dose you may need. Too much vitamin D can be toxic, so it's important to supplement mindfully and under professional guidance.

Food Sources of Vitamin D

While food won’t give you enough vitamin D to rely on exclusively, it can still help you top up your levels. Natural food sources include:

• Oily fish: Salmon, sardines, mackerel, and herring are among the richest sources.
• Egg yolks: Free-range eggs have higher levels of vitamin D than caged varieties.
• Beef liver: Not for everyone’s taste, but a traditional nutrient powerhouse.
• Mushrooms: Specifically UV-exposed varieties like portobello or shiitake can provide some vitamin D2.

These foods can complement your sun exposure or supplementation, but most won’t provide sufficient levels on their own, particularly in winter or during periods of limited sunlight.

The Link Between Vitamin D and Hormonal Health

Vitamin D plays a key role in hormone regulation, particularly in supporting reproductive and thyroid health. In women, low levels have been linked to PMS, PCOS, and even fertility issues. For men, vitamin D is essential for testosterone production and overall hormonal balance. A deficiency can contribute to mood instability, fatigue, and reduced libido in both sexes.

As many people on a paleo diet focus on rebalancing their hormones through real food and lifestyle changes, optimising vitamin D is a critical piece of the puzzle. Ensuring adequate levels helps stabilise mood, supports adrenal function, and enhances resilience to stress.

Vitamin D and Bone Density

Most people associate calcium with bone strength, but vitamin D is just as important — if not more so. Without enough vitamin D, your body struggles to absorb calcium from food. This means even if you’re consuming plenty of bone broth, leafy greens and sardines, you may not be benefiting fully if your vitamin D status is low.

In older adults, low vitamin D levels are associated with increased risk of osteoporosis and fractures. For younger people, ensuring adequate levels helps lay the foundation for strong bones later in life. If you follow a dairy-free paleo diet, monitoring your vitamin D becomes even more crucial for maintaining skeletal health.

Children and Vitamin D Deficiency

Children need vitamin D for proper growth, immune support and bone development. In Australia, where the slip, slop, slap campaign has successfully raised awareness about sun safety, many children now get very little unfiltered sun exposure. This has led to a resurgence of rickets in some areas — a disease caused by vitamin D deficiency resulting in soft, weak bones.

If you’re raising your kids on a paleo lifestyle, make sure they get some time in the sun each day. Encouraging outdoor play not only boosts vitamin D but also supports mental health, physical fitness and sleep. In cases where sun exposure is limited, a child-specific vitamin D supplement may be recommended by your healthcare provider.

When to Get Your Levels Checked

If you’re experiencing any of the symptoms mentioned earlier — from fatigue to frequent illness or mood swings — a simple blood test for 25-hydroxyvitamin D can give you answers. The ideal range varies by practitioner, but most integrative and functional medicine experts suggest levels between 75 to 120 nmol/L for optimal health (higher than the minimum reference range used in conventional medicine).

In Australia, you may need to request this test specifically from your GP, and it may not always be bulk billed, depending on your symptoms or medical history. Regardless, it’s a worthwhile investment if you suspect your vitamin D levels are suboptimal — especially heading into winter.

Final Thoughts on Vitamin D and Paleo Living

For those living a paleo lifestyle, vitamin D is one of the few nutrients that can’t be reliably obtained from food alone. It’s essential for immunity, mental wellbeing, hormonal balance, bone health, and energy levels. With so many people spending their days inside under artificial light, it's not surprising that deficiency is common — even here in sun-blessed Australia.

Whether it’s stepping outside for some midday sunshine, including wild-caught oily fish in your weekly menu, or taking a high-quality supplement after checking your blood levels, taking action to maintain healthy vitamin D levels will support every aspect of your health and wellbeing.

When was the last time you made a conscious effort to get some sun? It might just be the missing link in your wellness routine.

When did you last get your levels checked? Were you deficient?