Immunity & seasonal eating
Why we are more likely to get sick in winter?
At the end of summer when that first nip is in the air, it marks the start of cold and flu season. During our lifetime we experience an average of 200 colds – that’s 5 years of coughs, congestion, headaches and sore throats. These are caused by viral infection of the upper respiratory tract. The common cold is usually harmless although it might not feel that way at the time. The most common cold causing culprits are the rhinovirus family of which there are around 160 different cold causing ‘serotypes’ making it possible to have several colds one after another. Viral DNA changes frequently which makes the job of our immune system quite difficult and explain why we tend to get many throughout our lives. Although you can get a cold anytime, Rhinoviruses prefer cooler climes, which is, in part, why colds are more prevalent in winter. Studies show that the immune system is stronger during the summer. In addition, Lower infection fighting UV light in the dark winter months combined with cold-induced changes to the nasal immune system contribute to making us more susceptible in winter. Cooler weather drives people indoors and reduces vitamin D from sunlight - a key factor in regulating the immune system.
It’s not just infections that are more common in winter
It’s not only those seasonal runny noses that we all seem to suffer more in winter, a host of health conditions including heart attacks and strokes and even depression - are more common in winter, while people are healthier in the summer. Winter darkness can leave us waking feeling groggy. There is now real evidence supporting the common belief that this is down to seasonal changes in our immune system. These changes are primarily attributed to the varying activity of genes in our immune cells responding to environmental cues in the changing environment like sunlight (and to a lesser extent air temperature). Our internal body clock - known as our circadian rhythm - is coordinated by changes in daylight and explains why shorter days in winter can result in poorer health, research. The majority of our immune system cells contain genes controlled by the circadian rhythm. Some genes become more active in the summer months, while others became more active in the winter. For example, one gene involved in the body's anti-inflammation response was increased during the summer, while some involved in inflammation were increased in the winter. For example: During European winters the thresholds required to trigger an immune response is lower as a direct consequence of our coevolution with infectious organisms, which tend to be more prevalent during winter. The human immune systems will adapt to different seasonal variations with more pronounced differences between winter and summer as you move further from the equator.
Eat seasonally to support your body’s need.
Have you noticed that you crave different foods at different times of year? Just as our immune system is known to change with the seasons, cold weather brings a desire to eat warming hearty foods. This is an example of the tight link between our immune system and our neuronal system. Our local environment has us covered with the produce that is naturally providing us with the key required nutrients during each season. Eating seasonally also means you are more likely to eat the freshest produce and consume it at the time it was ripened – this is now known to preserve their phytonutrient properties. But this also creates a sense of community, is more like to come from smaller scale producers and benefits the local economy. On an intuitive level, it is theorised that we can benefit our microbiome by eating the seasonal foods that corresponds with our external environment.
The natural cycle of produce is perfectly designed to support our health. Building a lifestyle around seasonal foods helps facilitate the body natural needs. But there are other benefits too. Food grown outside of their season or natural environment need a lot more human assistance in forms of pesticides, to grow and look appealing to us. By choosing local and seasonal food, you are also more likely to get produce grown with minimal artificial support! And although there might not be much difference between the vitamin and mineral content, produce grown without pesticides can have up to 100 times more phytonutrients.
TOP TIPS TO SASS UP YOUR SEASON:
Think food first – focus on phytonutrient rich meals before pill popping vitamins & minerals.
Shop small & shop local – up your intake of seasonal produce by looking for local growers and farmers markets.
Economy and environment – when foods are in season, the price can go down. It’s also an environmentally friendly.
Get creative – Eating seasonally forces you to cook more and challenges your creativity; google a new recipe, or come up with a dish
Herbs and spices – an excellent way to increase diversity and variety in your meals is to add seasonal herbs and spices. They often pack a huge phytonutrient punch too.