We know more about food affecting our moods than ever before.
We're also starting to understand the relationship between your gut
and your mood.
Read the latest from Harvard Medical School newsletter
contributor, Dr Uma Naidoo, and her simple food recommendations for
a healthier gut and improved mood.
The human microbiome, or gut environment, is a community of
different bacteria that has evolved with humans to benefit both a
person and the bacteria.
Researchers agree that a person's unique microbiome is created
within the first 1,000 days of life, but there are things you can
do to alter your gut environment throughout your life.
Processed foods and gut health
What we eat, especially foods that contain chemical additives
and ultra-processed foods, affects our gut environment and
increases our risk of diseases.
Ultra-processed foods contain substances extracted from food
(such as sugar and starch), added from food constituents
(hydrogenated fats), or made in a laboratory (flavour enhancers,
It's important to know that ultra-processed foods such as fast
foods are manufactured to be extra tasty by the use of such
ingredients or additives, and are cheap to buy.
These foods are very common in the typical Western diet.
Some examples of processed foods are canned foods, sugar-coated
dried fruits, and salted meat products.
Some examples of ultra-processed foods are soft drinks, sugary
or savoury packaged snack foods, packaged breads, buns and
pastries, fish or chicken nuggets, and instant noodle soups.
Researchers recommend "fixing the food first" (in other words,
what we eat) before trying gut modifying-therapies (probiotics,
prebiotics) to improve how we feel.
They suggest eating whole foods and avoiding processed and
ultra-processed foods that we know cause inflammation and
But what does my gut have to do with my
When we consider the connection between the brain and the gut,
it's important to know that 90 per cent of serotonin receptors are
located in the gut.
In the relatively new field of nutritional psychiatry patients
are helped to understand how gut health and diet can positively or
negatively affect their mood.
When someone is prescribed an antidepressant such as a selective
serotonin reuptake inhibitor (SSRI), the most common side effects
are gut-related, and many people temporarily experience nausea,
diarrhea, or gastrointestinal problems.
There is anatomical and physiologic two-way communication
between the gut and brain via the vagus nerve.
The gut-brain axis offers us a greater understanding of the
connection between diet and disease, including depression and
When the balance between the good and bad bacteria is disrupted,
disease may occur.
Examples of such diseases include: irritable bowel disease
(IBD), asthma, obesity, metabolic syndrome, diabetes, and cognitive
and mood problems.
For example, IBD is caused by dysfunction in the interactions
between microbes (bacteria), the gut lining, and the immune
Diet and depression
Recent research suggests that eating a healthy, balanced diet
such as the Mediterranean diet and avoiding inflammation-producing
foods may protect against depression.
study outlines an Antidepressant Food Scale, which lists 12
antidepressant nutrients related to the prevention and treatment of
Some of the foods containing these nutrients are oysters,
mussels, salmon, watercress, spinach, romaine lettuce, cauliflower,
A better diet can help, but it's only one part of treatment.
It's important to note that just like you cannot exercise out of
a bad diet, you also cannot eat your way out of feeling depressed
We should be careful about promoting food as the only treatment
for mood, and when we talk about mood problems we are referring to
mild and moderate forms of depression and anxiety.
In other words, food is not going to impact serious forms of
depression and thoughts of suicide, and it is important to seek
treatment in an emergency department or contact your doctor if you
are experiencing thoughts about harming yourself.
Suggestions for a healthier gut and improved mood:
- Eat whole foods and avoid packaged or processed foods, which
are high in unwanted food additives and preservatives that disrupt
the healthy bacteria in the gut.
- Instead of vegetable or fruit juice, consider increasing your
intake of fresh fruits and vegetables. Frozen fruits without added
sugars/additives are a good choice, too.
- Eat enough fibre (male: 30 grams and female: 25 grams) daily
and include whole grains and legumes in your diet.
- Include probiotic-rich foods such as plain yogurt without added
- To reduce sugar intake at breakfast, add cinnamon to plain
yogurt with berries, or to oatmeal or chia pudding.
- Adding fermented foods such as kefir (unsweetened), sauerkraut,
or kimchi can be helpful to maintain a healthy gut.
- Eat a balance of seafoods and lean poultry, and less red meat
- Add a range of colourful fresh fruits and vegetables to your