Why Do Vitamin Deficiencies Increase After Summer? Symptoms and Solutions

As the vibrant Turkish summer fades, our exposure to sunlight decreases and our diets shift, which can rapidly deplete our body's vitamin reserves. Especially in autumn, vitamin deficiencies spike due to a drop in Vitamin D from shorter days and a changing variety of fresh produce. This triggers fatigue during seasonal transitions and leaves the immune system more vulnerable to illnesses.

• Decreased sunlight is the primary cause of post-summer Vitamin D deficiency.
• A drop in fresh vegetable consumption during autumn directly impacts Vitamin C and B reserves.
• Fatigue, muscle aches, and frequent illnesses are the most common signs of a deficiency.
• Rather than taking supplements blindly, a blood test is essential to identify specific shortages.
• To support immunity, focus on colourful, seasonal fruits and vegetables.

What is Post-Summer Vitamin Deficiency and Why Does It Increase?

Our bodies constantly rely on externally sourced vitamins and minerals to function optimally. During the long, sunny days of summer—whether you are strolling along the Bosphorus or enjoying the Aegean coast—we spend more time outdoors and have easy access to fresh foods, meeting these needs naturally. However, as September arrives, cooler weather, shorter days, and more time spent indoors bring about a physiological shift.

The changing angle of the sun's rays drastically reduces our skin's capacity to synthesise Vitamin D. Additionally, the light, nutrient-rich Mediterranean diets of summer often give way to heavier, carbohydrate-rich, and less varied autumn meals. Many people who follow the principles to stay fit and energetic in the summer heat find themselves moving less as the weather cools. Physical inactivity slows the metabolism, indirectly affecting the absorption of vitamins from food. When all these factors combine, the body's defence mechanisms weaken, and clinical symptoms of deficiency begin to appear.

What Are the Symptoms of Vitamin Deficiency?

Vitamin deficiencies usually develop slowly and silently. Although the body initially tries to compensate by using its reserves, specific symptoms emerge once these stores are depleted. A lack of each specific vitamin affects different systems, sending unique signals.

Symptoms of Vitamin D Deficiency

Post-summer Vitamin D deficiency is one of the most common conditions we see. Vitamin D is critical for regulating the immune system and protecting bone health by enabling calcium absorption. A deficiency often manifests as difficulty waking up in the morning, widespread body and bone aches throughout the day, muscle weakness, and cramps. Furthermore, increased hair loss, unexplainable low moods, a tendency towards depression, and delayed wound healing are also frequent signs.

Symptoms of Vitamin C Deficiency

Because Vitamin C is water-soluble and cannot be stored in the body, it must be consumed daily. As a powerful antioxidant, Vitamin C supports collagen production and acts as a shield against infections. A lack of it can lead to bleeding gums, dry and flaky skin, and a tendency to bruise easily. The most prominent sign, however, is catching upper respiratory infections like colds and the flu much more frequently, and taking longer than usual to recover.

Symptoms of B-Complex Vitamin Deficiencies

B vitamins, such as B12, B6, and folic acid, are essential for a healthy nervous system and the production of red blood cells. As our diets change in the autumn, our intake of these vitamins may drop. A B vitamin deficiency often causes numbness and tingling in the hands and feet, forgetfulness, difficulty focusing, and what is commonly known as 'brain fog'. Recurrent mouth ulcers (canker sores), a red and burning sensation on the tongue, and heart palpitations are also typical indicators of B12 and folic acid deficiencies.

An Autumn Nutrition Guide to Support Immunity

Creating a diet rich in immune-boosting vitamins during seasonal transitions is the most natural way to ward off illness. Just as we protected our health in the summer with the 7 superfoods of July, we must turn to the seasonal produce nature offers us in autumn.

Here are the foods you should not miss on your autumn table:

• Citrus Fruits and Pomegranates: Mandarins, oranges, lemons, and grapefruits are pure Vitamin C powerhouses. Pomegranates, a staple in Turkish autumn markets, prevent cellular damage and support immunity thanks to their potent antioxidants.
• Dark Green Leafy Vegetables: Vegetables like spinach, Swiss chard, and black cabbage (karalahana) are highly rich in iron, folic acid, and Vitamin A. Squeezing a little lemon over these greens will enhance your body's iron absorption.
• Pumpkins and Carrots: Rich in beta-carotene (a precursor to Vitamin A), these vibrant orange vegetables strengthen the respiratory membranes, creating a barrier against viruses.
• Nuts and Seeds: Walnuts, almonds, hazelnuts (a beloved Turkish staple), and pumpkin seeds protect the nervous system and reduce fatigue through their Vitamin E, zinc, and healthy fats.
• Root Vegetables: Celery root, radishes, and Jerusalem artichokes are rich in fibres that nourish the gut flora. A healthy gut microbiome is the foundation of a robust immune system.

Diagnosis: How Are Vitamin Levels Measured?

Diagnosing vitamin deficiencies requires a comprehensive blood test at a hospital. For patients presenting with complaints of fatigue and sluggishness, a doctor will first conduct a detailed physical examination and listen to their medical history. Dietary habits, medications, and lifestyle are all carefully reviewed.

Diagnosis typically involves a morning fasting blood sample to check a complete blood count (hemogram), Vitamin D (25-OH Vitamin D), Vitamin B12, folic acid, iron, and iron-binding capacity. These tests reveal the true underlying cause of fatigue. Sometimes, what seems like a vitamin deficiency may actually be masking other health issues, such as thyroid dysfunction or anaemia. Therefore, laboratory testing is essential for an accurate diagnosis.

Treatment: Home Care and Hospital Treatments

Treatment for a vitamin deficiency is tailored to the severity of the shortage and the patient's overall health. For mild deficiencies, adjusting dietary habits and taking oral supplements prescribed by a doctor are usually sufficient. The specific vitamins needed in autumn must be determined individually based on blood test results.

For a Vitamin D deficiency, supplements are provided in drop, capsule, or ampoule forms. If a Vitamin B12 deficiency stems from an absorption issue in the gastrointestinal tract, oral pills may not work. In such cases, Vitamin B12 is administered via intramuscular injection. Vitamin C deficiencies can typically be resolved easily through diet. Throughout the treatment, drinking plenty of water, getting regular sleep, and taking brisk walks outdoors will speed up recovery. Follow-up blood tests are used to ensure your vitamin stores have been successfully replenished.

Complications and Risk Groups

If left untreated, vitamin deficiencies can lead to chronic fatigue syndrome, osteoporosis (bone thinning), permanent nerve damage, and a compromised immune system. When the fatigue associated with seasonal changes is ignored, it can severely disrupt a person's professional and social life.

Certain individuals are at a higher risk of vitamin deficiencies. Those working in indoor office environments all day are prone to Vitamin D deficiency due to a lack of sunlight. Older adults often experience reduced B12 absorption due to decreased stomach acid. Pregnant women, nursing mothers, vegans, vegetarians, and individuals with chronic intestinal conditions (such as celiac or Crohn's disease) must be especially vigilant during seasonal changes and keep up with their routine check-ups.

When to See a Doctor

A mild sense of sluggishness lasting a few days during seasonal transitions can be considered normal. However, certain signals from your body indicate that you should seek medical attention without delay. It is highly important to consult your doctor if you experience one or more of the following symptoms:

• Severe fatigue and exhaustion that make it difficult to get out of bed in the morning.
• Widespread muscle, joint, and bone pain that hinders your daily tasks.
• Numbness, tingling, or loss of sensation in your hands and feet.
• Frequent infections and illnesses that last much longer than usual.
• Unexplained hair loss, pale skin, and bruising for no apparent reason.
• Brain fog, severe forgetfulness, and sudden mood swings.

If you experience sudden and severe symptoms such as shortness of breath, chest pain, a feeling of fainting, or confusion, you should immediately call 112 for emergency services or visit the nearest hospital's emergency department.

The Process at BHT CLINIC

At the Internal Medicine and Nutrition & Dietetics departments of BHT CLINIC İstanbul Tema Hastanesi, all health issues related to seasonal transitions are meticulously evaluated. Our specialist doctors will plan the most appropriate laboratory tests for your symptoms to identify any deficiencies. Based on the results, a fully personalised supplementation and nutrition programme is created just for you.

Blood collection and laboratory services at our hospital are carried out quickly and reliably. Bringing any previous blood test results and a list of your regular medications to your appointment will help expedite the process. For unexpected and severe symptoms, our 24/7 Emergency Department is always ready to assist you. For a comprehensive evaluation and a healthy autumn, you can book your appointment immediately through BHT CLINIC.

Frequently Asked Questions

Which vitamins should be taken in autumn?

To support immunity in autumn, Vitamin D, Vitamin C, zinc, and B-complex vitamins are generally needed. However, exactly which vitamins and what dosages are required must be determined entirely by your blood values and your doctor's recommendation.

What are the symptoms of Vitamin D deficiency?

The most prominent symptoms include widespread bone and muscle pain, a constant feeling of fatigue, difficulty waking up in the morning, hair loss, and an unexplainable low (depressive) mood.

What helps with fatigue during seasonal transitions?

To alleviate seasonal fatigue, it is highly effective to maintain a healthy sleep schedule, drink plenty of water, take regular walks outdoors, and eat a balanced diet of seasonal fruits and vegetables. If complaints persist, blood levels should be checked.

When should I take vitamin supplements?

The absorption of vitamins varies by type. Fat-soluble vitamins like Vitamin D should be taken on a full stomach (especially after a meal containing healthy fats), while certain B vitamins and iron supplements may be better absorbed on an empty stomach. Your doctor or pharmacist will advise you on the best time to take them.

This article is for informational purposes only; please consult your doctor for diagnosis and treatment.