We’re hearing a lot about the relationship between inflammation and diet. Numerous diets and foods are being touted to reduce inflammation – but what does this mean exactly? Can what we eat actually reduce inflammation? What is this ‘inflammation’ exactly?
Let’s start with exploring what inflammation is – inflammation is a response by our immune system, as a normal reaction to an infection and injury. This response is actually protective because it helps to remove harmful agents and enables tissues to heal. This inflammatory process is regulated and eventually stops once the infection or injury is healed.
When Inflammation is Harmful
Inflammation can be damaging when it is uncontrolled, and excessive damage to tissue can result. High concentration of cell signalling proteins (cytokines) including Tumour Necrosis Factor-A and Interleukin-6, could cause tissue injury, adipose tissue wasting, muscle wasting and bone mass loss.
Overtime low-grade, continuous release of pro-inflammatory cytokines (Interleukin-6 and Tumor Necrosis Factor-A) within the vascular wall affect the inner lining of the blood vessels, known as the endothelium. This can lead to endothelial dyfunction. This could lead to the initiation of cardiovascular disease and atherosclerosis.
Excessive inflammatory processes of the endothelium is a mechanism behind:
- Metabolic syndrome/insulin resistince
- Obesity
- Type 2 DM
- Cardiovascular disease
- Alzheimers
- Malnutrition
- Rheumatoid arthritis
- IBD
- Critical illness
- Cancer
- Depression
How can food impact inflammation?
The metabolism of food is intimately associated with a stress reaction in the cell, in response to the ingestion of food. The immune response is dependent upon the presence of both macro and micronutrients for optimal functioning. Therefore it is possible that the food we eat can influence the inflammatory process.
Nutrients The Can Decrease Inflammation:
1. Phytochemicals
ie carotenoids, phenolic compounds and lignans.
- They target multiple signalling pathways (ie call proliferation, apoptosis, angiogenesis, and inflammatory signalling pathways)
- They have antioxidant properties
Food examples: sweet potatoes, dark leafy greens, tomatoes, soybeans, legumes, oats
2. Flavonoids
- Shown to decrease energy intake/increase energy expenditure
- Flavonoids can increase glucose uptake in muscle and decrease glucose uptake in adipose tissue
- Inhibitions the synthesis and activities of different pro-inflammatory mediators such as eicosanoids, cytokines and C-reactive protein.
Food examples: berries, red wine, green tea, apples, cocoa, onions, leafy greens
3. Omega 3 Fatty Acids (EPA/DHA/MUFA/PUFA)
- Substitution of omega 6 with omega 3s can improve the synthesis of eicosanoids- eicosanoids have fewer inflammatory properties
Food examples: fatty fish (salmon and rainbow trout), chia seeds, flax seeds and walnuts
4. Fibre & Low GI foods
- Decreases glycemic response, which in turn decreases insulin response. High insulin levels promote inflammation
Food examples: bran, barley, bulgar, pasta/noodles, sweet potato, legumes
5. Magnesium
- Maintains intracellular homeostasis
- Reduces endothelial dysfunction at the vascular level and decreases the risk of insulin resistance, type 2 diabetes and coronary heart disease
Food examples: legumes, nuts, seeds, fish and whole grains
6. Arginine
- Your body can synthesize this amino acid, however higher amounts are needed when your body is under stress
- Arginine helps form nitrous oxide, which is a vasodialator – this helps with blood flow and maintains cardiovascular health
- Essential for normal enthothelium-dependent vasodilation
Food examples: seafood (tuna, cod, shrimp), poultry, red meat, legumes, nuts and seeds (sunflower seeds, pumpkin seeds and peanuts)
Nutrients The Can Increase Inflammation
1. Common Allergens
IgE antibodies are release which react with food, chemicals and cause inflammation. More common trigger foods include milk, eggs, peanuts, fish/shellfish, soybeans, wheat
2. Meat Proteins
- Can affect endothelial function
- Thought to be related to the release of endotoxins from bacteria in gut
3. Refined Sugars & Starches
- Cause a rapid increase in blood sugar and insulin levels – high insulin levels lead to inflammation
- Leads to hunger and a decrease in fat oxidation
- Fructose consumption can impact satiety hormones
What about Saturated Fat?
- According to systematic reviews, saturated fat consumption from dairy was not associated with increased LDL
- There was neutral effects on lipids and inflammation – it depends on the source of saturated fat
- Cheese, even though it is high in fat, can be beneficial in reducing inflammation
In Summary
- An inflammatory response involves the immune system
- Inflammation is a normal reaction to acute stress, however becomes damaging when it is over-activated and can contribute to metabolic disease and cell damage
- Nutrition can impact inflammation in many ways
- Aim for a diet rich in various phytochemicals, flavonoids, omega 3 fatty acids, fibre and low GI foods, magnesium and arginine
- Aim to minimize refined sugars and starches and don’t overdo meat proteins
- Saturated fat from dairy doesn’t appear to significantly contribute to inflammation