Lecture 20: Food And Mood Flashcards
(12 cards)
What is the prevalence of depression in and out of NZ?
Globally: 5% of adults
NZ: 1/6 adults
Explain nutritional psychiatry and the link between dietary patterns and depression
Nutritional psychiatry = research field in response to the need for diverse strategies to prevent and treat mental health disorders
Link: “Traditional” dietary patterns characterized by vegetables, fruit, meat, fish and whole grains lowers the risk of depression, while a “Western” diet is associated with increased risk.
What does most nutritional psychiatry research consist of and what is one thing to keep in mind?
Observational research; in observational research we need to keep in mind that relations are not causal, food does not only influence mood, but mood also influences food.
Explain what was done in the SMILES trial
It was the first RCT investigating the effects of dietary change on depressive symptoms for people with moderate-severe depression.
- 1-2 weeks, single-blinded, randomized
- 67 adults (72% female) with moderate to severe depression
- Modified Mediterranean-style diet group (active) vs. Social support group (control)
- Behavior change techniques incorporated for Mod/Med group; nutrition counseling - goal setting, skill development, food hampers, resources kits
—> not for controls
What are 4 ways in which we need to be careful when interpreting the results of the SMILES trial
- Expectation bias potentially influencing outcomes
- Poor diet quality as an inclusion criteria
- Greater drop-outs on control (9 v 2)
- Differences in intervention ‘intensity’, and potential effects of behavioural activation
What are 4 biological links between diet and depression?
- Inflammation (maintaining a healthy weight can dampen inflammation)
- Oxidative stress (antioxidant vitamins/minerals can ameliorate oxidative stress)
- Gut-brain axis (fibre, polyphenols and fermented foods modify the composition and output of the gut microbiota)
- Brain plasticity (Omega-3 fatty acids, probiotics and polyphenols may be able to increase BDNF and enhance neurogenesis)
What is the gut microbiome?
The human GI tract represents one of the largest interfaces (250 - 400 m2) between the host, the environment and antigens in the human body. The GI tract is home to a community of microbes (gut microbiota), with HUNDREDS-fold greater genetic material than the human genome (gut microbiome).
There is a mutually beneficial between us (the host) and our microbes. The gut microbiome is like a delicate ecosystem, which thrives on harmony and balance (eubiosis). However, a loss of balance can occur, where we get an imbalance in the type of microbes present and their output (dysbiosis).
What are the 4 roles of the microbiome?
- Nutrition - Breaking down food and synthesizing nutrients
- Pathogen resistance - Alarm bell against invading microbes
- Immunity - Trains and maintains our immune system
- Communication - Sends signals to other organs
Microbiome —> Microbial outputs (eg. metabolites) —> host health status —> microbiome
What constitutes a healthy microbiome?
We are not exactly sure about what is best, but the one thing scientists agree on is that greater microbial diversity reflects a healthy microbiome.
—> People who eat at least 30 different plant-based foods a week had more diverse gut microbiome than people who ate less than 10, and it was also an abundance of “good bacteria”
—> diversity makes it thrive ad leads to resilience and capacity to produce it’s function even in tougher times
When is the window for influencing the microbiome the most significantly?
From 0-3 years old, here there is a lot of room for development, and after it is pretty much the same.
Foundation microbiome = initial microbial community that form in the gut during infancy
Established microbiome = mature and relatively stable microbial community in the gut
What is the most important component of the diet for the health of the gut microbiome?
Dietary fibre: it is the preferred fuel source, because it is resistant to breakdown by human enzymes but our gut microbes have the capacity to break down the bonds between glucose monomers in dietary fibre.
—> Animal research has shown that
diets low in dietary fibre can lead to intergenerational loss of species and microbial richness.
Explain the difference between prebiotics, probiotics, and fermented foods/beverages
Prebiotics = Food components that are selectively used by host micro-organisms and confer a health benefit
Probiotics = Live bacteria and yeasts that, when administered in a viable form and adequate amounts, are beneficial to human health
Fermented foods/beverages = Foods/beverages that have undergone fermentation by bacteria. Can contain live microorganisms and microbial outputs.
