Nutritional Guidance for Seasonal Transitions

Alice: Thank you for having me. I’m Alice Nguyen, MSc. in Sports Nutrition. I graduated with a BS from medical university and completed my MSc at Liverpool John Moores University. I specialize in performance nutrition, meaning I help people improve their health, energy, and body composition through personalized nutrition.

Reporter: The weather has been quite unpredictable lately – hot one day, the next suddenly cool. How do such changes affect one’s body and overall health?

Alice: Rapid temperature shifts trigger stress responses in the body. When the environment changes quickly, the body needs to constantly adjust its thermoregulation, circulation, and hormonal balance. This can lead to lower innate immunity because more energy is spent on maintaining body temperature; changes in airway sensitivity, making the respiratory system more reactive; and mild dehydration, because cooler weather reduces thirst signals, while humidity changes increase fluid loss. All of those mechanisms increase susceptibility to fatigue and infection.

Reporter: Many people say they feel tired or easily catch a cold during this period. Why does that happen, and what role does nutrition play in keeping our body strong?

Alice: During this season, immunity often weakens due to reduced mucosal immunity. Dry air affects the mucous membranes in the nose and throat, weakening their ability to trap viruses. A higher inflammatory load may also contribute; the immune system becomes more taxed adapting to environmental stress. Nutrition supports immunity by providing the substrates needed for immune cell turnover. For instance, protein supplies amino acids for antibody production; antioxidants—vitamins C and E and polyphenols—reduce oxidative stress caused by environmental changes; and omega-3 fatty acids manage inflammatory pathways.

Reporter: What types of food should we focus on to boost our immune system and stay healthy during the change of seasons?

Alice: To improve our immunity, we can focus on several key nutrients and food types. Proteins are vital for antibody production and immune cell repair. You can find quality sources in animal products like pork, beef, eggs, and chicken. Vitamin C, found in citrus fruits and berries, boosts white blood cell activity. Vitamin A is essential for keeping respiratory and gut linings healthy, and vitamin D, which many of us might lack in winter, helps regulate immune signaling. Probiotics and fiber support gut health, impacting immunity positively. Lastly, hydration plays a pivotal role since lymph, the fluid that carries immune cells, requires water to circulate effectively.

Reporter: What are some simple examples of a balanced breakfast or lunch that would be good for this time of year?

Alice: I’d suggest simple, easy-to-prepare meals. For breakfast, oatmeal topped with yogurt, fruit, and nuts—like walnuts and chia seeds—offers probiotics, antioxidants, and slow-releasing carbohydrates. For lunch, consider rice with grilled fish and vegetables, which provides protein, carbohydrates, vitamins, and fiber. If you prefer noodles, a bowl of chicken Pho with fresh herbs is nutritious as well. Vegetarians might like tofu stir-fried with beans, tomatoes, and greens. These meals, rich in proteins, micronutrients, and fiber, help stabilize your immunity.

Reporter: Some people rely on vitamins and other dietary supplements instead of eating fruits and vegetables. Can supplements replace real food?

Alice: Supplements can be useful but can’t fully replace whole foods. Real food contains fiber and polyphenols, essential compounds that work synergistically to reduce inflammation and support immunity. Still, if you’re not getting enough nutrients, supplements can fill the gap—like vitamin D during winter, which we typically obtain from sunlight, or omega-3 fatty acids, if you don’t consume fish regularly.

Reporter: What daily habits can help people with busy lifestyles maintain healthy nutrition?

Alice: For busy individuals, here are some practical tips: First, include protein in every meal—aim for a protein source at breakfast, lunch, and dinner. Second, increase your daily intake of fruits and vegetables for more fiber and vitamins. Third, prepare grab-and-go snacks, such as yogurt, nuts, or boiled eggs, for quick nutrition. Fourth, stay hydrated—drink water consistently throughout the day. Lastly, consider pre-cooking proteins and vegetables to save time during meal preparation.

Some tips that can make a big difference in terms of nutrient intake

Reporter: You work closely with professional athletes. Are there any nutrition lessons from the sports world that ordinary people can use?

Alice: Absolutely! Athletes emphasize the importance of consistent nutrition. They don’t wait until they’re fatigued or unwell to eat right; they make it a daily habit. Two key takeaways are: first, eat for recovery rather than just hunger. After intense training, athletes combine protein, quality carbohydrates, and vitamins to replenish energy and bolster immunity. Second, hydration is crucial. Regular water intake significantly aids concentration and immune function, and these strategies are applicable to everyone, not just athletes.

Reporter: What’s your key message for listeners who want to stay healthy all year round?

Alice: The important thing is to focus on small, consistent habits rather than drastic changes. You don’t need expensive foods; just a balanced diet rich in proteins, vegetables, whole grains, and healthy fats, along with adequate hydration, will establish a robust immune foundation. Focus on maintaining this foundation as a priority before adjusting your diet to meet specific goals.

Reporter: Thank you very much, Alice, for all your insights. That’s all for today’s episode of Doctor at Home. We hope these tips will help you all stay healthy and energized through the change of season. We hope you’ll join us for the next episode.