Nutrition and Lifestyle connections to Depression: Part 3

Part Three: The Gut Brain Axis

In Parts One and Two, we explored the many causes of depression and how nutrition can play a role in supporting mental health. But what about the connection between your gut, hormones, and brain? These systems are constantly communicating with one another, and when something isn't functioning as it should, it can affect how you feel both physically and emotionally. In this final part of our series, we'll explore the gut-brain connection, how thyroid and sex hormones can influence mood, and the everyday lifestyle habits that can support your mental well-being.

The Gut-Brain Axis

• Hormones

• Immune system

• Vagus nerve

Hormones

Test and treat for hormonal imbalances

Hormones can affect mood - and hormone imbalances are a common but often-overlooked factor in depression.

If you’re being treated for depression, your doctor should check for levels of key hormones - and correct imbalances.

Thyroid Hormones

Low levels are the most common problem.

Common symptoms include:

• Memory and concentration problems

• Low sex drive

• Constipation

• High cholesterol

• Obesity

• Low blood sugar (hypoglycemia)

• Muscle aches and pains

• Dry skin

• Acne

• Eczema

• Hair loss

• Recurrent infections

• Irregular menstrual periods

• Severe premenstrual syndrome

• Ovarian cysts

• Endometriosis

• Fluid retention

• Intolerance to cold

• Lower sweat production

Inaccurate testing, ineffective treatment

Even when doctors check for thyroid hormones - and that’s nowhere near enough - the main test they use isn’t very accurate.  Usually they do not check for levels of free T3 and free T4 in the blood. TSH isn’t a thyroid hormone - it’s released by the pituitary gland in the brain, which uses TSH to tell the thyroid gland the body needs more T3 and T4. Basically, this blood test doesn’t answer the question, “Are your levels of thyroid hormones low?”

A high TSH means the thyroid is pumping out too little hormone; a low TSH means too much; and a balanced TSH means the thyroid is working just right.

Many people with a thyroid problem might be misdiagnosed on the basis of a TSH Test - that is, they’re told they don’t have an under- or overactive thyroid, when in fact they do! In my clinical experience, that includes many people with depression.  Research direct from Mayo clinic tells us low t4 in particular is a risk factor for depression.  

Thyroid antibodies

In some cases, low thyroid functioning is caused by an autoimmune disease: Hashimoto’s thyroiditis, in which the immune system attacks the thyroid as if it were a foreign invader, unbalancing hormones. This produces thyroid peroxidase (TPO) antibodies and antithyroglobulin (ATG) antibodies, a sure sign that your thyroid is under attack..

Sex Hormones

The sex hormones testosterone, estrogen, and progesterone can play a role in depression.

The Adrenal Glands 

Theres another adrenal hormone that’s far more abundant than adrenaline, and plays a big role in everyday life and health: DHEA (dehydroepiandrosterone).

Without DHEA, it’s harder for your body to produce the sex hormones testosterone or estrogen. DHEA also plays a role in the strength of the immune system, in levels of energy and fatigue, and in maintaining healthy bones.

DHEA influences mood. Lower DHEA levels, more recurrent depression.Depressed people produce less DHEA as well.  

Lifestyle Healing

Other factors that reduce the risk of depression

• Healthy sleep

• Healthy whole foods

• Regular physical activity

• Less sedentary behavior

• Frequent social connection

• Minimal alcohol consumption

• Never smoking

Lifestyle is more important that genetics

1. SSRIs/SNRIs have a profound effect on the way your brain functions.

2. They make serotonin bind to the serotonin receptors on the surface of neurons for longer periods of time - triggering your body to produce less serotonin.

3. When you stop taking the SSRI/SNRI, you go into a kind of serotonin shock from low levels of serotonin - with headaches, brain zaps, irritability, insomnia, intense agitation.

4. Those with the worst symptoms have the most significant nutritional deficiencies

5. That’s because several nutrients - like zinc, vitamin D, folate, B6, and B12 - are essential cofactors in the creation of serotonin.

6. If you’re deficient in one of those nutrients, or you’re genetically programmed with a need for higher levels of the nutrient - when you stop the SSRI/SNRI, and your body tries to produce more serotonin, it can’t, because it doesn’t have the raw materials from serotonin production.

7. To safely deprescribe from SSRIs/SNRIs, you need to test for the levels of these nutrients, use targeted nutritional supplementation to correct low levels, and only then start your taper off your SSRI/SNRI.

8. Work in partnership with your doctor to do just that!

Depression is complex, and there's no one-size-fits-all approach to managing it. Throughout this three-part series, we've explored how nutrition, hormones, gut health, and lifestyle habits can all play a role in our mental and emotional well-being. While we can't always control every factor that contributes to depression, there are steps we can take to support our health.

Start with the basics: prioritize quality sleep, nourish your body with whole foods, stay physically active, and make time for meaningful connections. If you're struggling with symptoms of depression, work with a qualified healthcare provider to explore possible contributing factors and develop a treatment plan that's right for you. Small lifestyle changes can make a difference, but they work best as part of a comprehensive approach that may also include therapy and medication.

Remember, taking care of your mental health is just as important as taking care of your physical health. You deserve support, and you don't have to navigate depression alone.