Lemon's Role In Boosting Immune Health

Introduction

The immune system is the most vital component in the body, made up of cells, proteins, and organs. It has a variety of functions such as  distinguishing between harmful and helpful bacteria, fighting  harmful bacteria by recognising and destroying them  as well as  it can  fight disease-causing  cells, for example, cancer cells.^[1] Without the immune system, the body cannot defend itself from pathogens (harmful germs), causing an individual illness. 

The immune system cells  are divided into two immune responses, innate and adaptive.^[2] The innate response is fast but is not able to remember and recognise a pathogen, whereas an adaptive response can do so . 

When the immune system responds, it results in symptoms such as swelling, pain, and feeling heat, i.e., inflammation. This shows that the tissue is damaged while the immune system defends the body. 

diet plays a crucial factor for  the cells in the immune system to function at optimum capacity. Some foods are more useful for the immune system than others, such as lemons, which  can potentially help with the development and maintenance of the immune system. 

Nutritional composition of lemons and the benefits of vitamin C

The nutritional composition of 100g of lemons without their peel is:^[3]

-       89 g Water

-       26 mg Calcium

-       0.6 mg Iron

-       8 mg Magnesium

-       16 mg Phosphorus

-       138 mg Potassium

-       53 mg Vitamin C

-       0.02 mg Riboflavin

-       11 µg Folate

-       22 IU Vitamin A

-       0.15 mg Vitamin E

Lemons can  benefit your health in an array of ways such as:^[4]

-       Lowering stroke risk

-       Lowering blood pressure

-       Preventing cancer

-       Maintaining a healthy complexion 

-       Preventing asthma

-       Increasing iron absorption 

-       Boosting the immune system

-       Weight loss

Lemons contribute specifically to immune health. Lemons contain vitamin C, as seen in the nutritional chart above, which is the most vital component. Vitamin C is an effective antioxidant which protects proteins, carbohydrates, and lipids from damage by cell metabolism (chemical processes in the body) and pollutants.^[5] The recommended daily intake of vitamin C is 75 mg for women over 19 and 90 mg for men.

Without vitamin C a deficiency called scurvy can be developed and this can cause:

-       Fatigue

-       Inflammation of the gums

-       Redness

-       Joint pain

-       Slow healing wounds

-       Loose teeth

-       Depression

Vitamin C can build up in cells capable of engulfing bacteria, such as neutrophils, and can  enhance:

-       Chemotaxis- the movement within the cell when a stimulus is added

-       Phagocytosis- the engulfing of harmful bacteria

-       The production of reactive oxygen species

-       The killing of microorganisms such as bacteria and viruses

This emphasises that vitamin C is a key component for boosting immune health.

Lemons contain a range of antioxidants such as:^[6]

• Proanthocyanidins- this can enhance chemotherapy treatments, anti-tumour action and destroy cell toxicity.^[7]
• Flavonoids have anti-cancer, anti-inflammatory, and anti-viral properties.^[8]
• Hesperidin- this has anti-inflammatory characteristics.^[9]
• Eriocitrin- these reduce metabolic disorders and obesity.^[10]
• Vitamin E protects cells from toxic damage.^[11]
• Vitamin C- this enables metabolism, iron absorption, the formation of collagen and cartilage.^[12]

Benefits of lemons for immune health

Enhanced white blood cell function:

Vitamin C is outlined above to enhance the killing of harmful bacteria. It specifically does this through its major role in enhancing lymphocytes: B cells and T cells. A lymphocyte is a type of white blood cell that is a part of the immune system. B cells produce antibodies that destroy bacteria and T cells destroy the cells in the body that have been affected by a virus.^[13] Vitamin C allows for the enhancement of B cells and T cells, leading to their differentiation (the specialisation of features) and proliferation (the increasing of cells). 

Infections are common when white blood cells are low, and this can cause symptoms such as:^[14]

-       High temperature 

-       Chills

-       Sore throat

-       Mouth sores

-       Toothache

-       Rashes

-       Fatigue

-       Flu-like symptoms 

Reduction of inflammation:

When a wound hurts, turns red and swells up, this is a sign of inflammation. The wide presence of antioxidants enables lemons to exhibit anti-inflammatory properties. Additionally, flavonoids and hesperidin are prime examples of these anti-inflammatory antioxidants. They can do this by inhibiting certain enzymes and transcription factors which are in charge of inflammation.^[15] Flavonoids are important for inflammation as unregulated inflammation can cause: cardiovascular disease, cancer or even allergies. 

Some symptoms of inflammation include:^[16]

-       Heat

-       Swelling

-       Redness

-       Pain

-       Loss of function

-       Fever

-       Changes in blood like an increase in immune cells

Improved digestion:

The gut contains microbiota (microorganisms) which break down substances for digestion. This can affect the strength, permeability, and integrity of the gut and, in turn, can influence the immune system.^[17] It has been known that disruption to this gut microbiota causes immune system dysfunction. Therefore this can lead to metabolic diseases, cardiovascular diseases, immune diseases, and neurological disorders. It can also lead to autoimmune disorders (a disease caused by antibodies).^[18] This is because the gut microbiota can affect and disturb the immune system’s ability to distinguish between foreign substances and itself. Furthermore, patients with autoimmune diseases often exhibit damaged gut barriers, making them more susceptible to harmful bacteria. 

Some symptoms of poor gut health include:^[19]

-       Sleep issues

-       Rashes

-       Sugar cravings

-       Fatigue

-       Mood swings

-       Weight gain or loss

The consumption of lemon water may aid digestion. The presence of vitamin C in lemons increases the secretion of bile in the gastrointestinal tract, improving the digestion of food.^[20] Additionally, lemon contains citric acid which also increases acids like bile in the stomach, further assisting the breakdown of food substances.^[21]

Practical ways to incorporate lemons into the diet

While lemons are known for their sour nature, they can be included in many recipes and foods.

There are numerous ways to incorporate lemons into your daily diet. Some may include:^[22]

1. Warm lemon water: this allows you to reduce your sugar intake, keeping you hydrated while also providing you with vitamin C and antioxidants.
2. Salad dressings: This refreshing use is great for all salads. Simply add lemon juice on top or incorporate it into a vinaigrette. 
3. Marinades: Coat your fish, vegetables, and chicken with fresh lemon and herbs. Not only can the juice make a tasty addition, but the zest is packed with nutrients and benefits. You can grate it and put it into your food to give it a zesty boost.
4. Sprinkle it over your vegetables: while you cook add some lemon juice to your roasted vegetables to enhance both the flavour and health benefits.
5. Desserts: Lemons can be incorporated into savoury foods and sweet treats such as lemon cakes and custard. 
6. Add it to your favourite juice or smoothie: this can be added as a natural sugar in both smoothies and juices and can be a great addition to  other fruits and vegetables. 

Lemons are shown to be quite versatile and can be included in both savoury and sweet recipes.

Precautions and considerations

Although lemons possess a range of health benefits, there are a few side effects related to its overconsumption, this could include:^[23]

Tooth decay- lemon juice is acidic which can cause enamel (the top coating of the tooth) to wear away over time. To avoid this avoid brushing your teeth after consuming lemon or drink lemon water with a straw. 

Migraines- in citrus fruit there is a component called tyramine, which is responsible for aggravating migraines. This can be controlled by reducing the consumption of citrus fruit. 

Stomach issues- lemons can trigger GERD (gastroesophageal reflux disease) or acid reflux, which can be identified by its burning feeling in the stomach, heartburn, frequent urination, and nausea.

Hosts harmful bacteria- there are microorganisms on the outside of the peel that can cause harm. It is best to squeeze the lemon into your drink and wash the outside thoroughly if using the zest.

Worse canker sores- these are mouth ulcers which appear on the lips, gums, tongue, and cheeks. Lemon is able to irritate these in high consumption.

Some precautions to take are:

• Pregnant and breastfeeding women: lemon is safe for these groups of people in their normal diet. However, the consumption of large amounts is still being determined , therefore it is beneficial to consult with your doctor if unsure.
• Always wash your lemons to destroy any harmful bacteria 
• Always follow directions on products which contain lemon to regulate consumption-   

Summary

In conclusion, lemons can provide various benefits, from their vitamin C content to their antioxidants. While these components can address various health issues, their primary role is in boosting immune health. It is able to do this by locating and destroying harmful pathogens and enhancing white blood cell function. Its antioxidant properties can also help with inflammation and digestion, which is directly correlated with immune health. There are many ways to incorporate this fruit into your diet, from savoury to sweet recipes, but one risk to consider is the overconsumption of lemon due to several side effects it can cause.