Building and supporting vibrant health with functional medicine, science-based nutritional therapy & therapeutic lifestyle change.
Building and supporting vibrant health with functional medicine, science-based nutritional therapy & therapeutic lifestyle change. 

I'm a registered Nutritional Therapist & a Functional Medicine practitioner - Dip. CNM; Dip.FMU; mBANT; mCNCH



I followed irresponsible diets out of sheer ignorance for more than the first 30 years of my life. For 20 years I refused to eat animal protein! Then for 10 years I avoided all fats!
The results of my lack of information regarding diets & nutrition lead to a painful outcome: malnourishment, demineralisation, and many problems giving birth to my only child.
As I had developed severe anemia too, due to my vegan choices, once my son was delivered -in a traumatic experience, by the way, that lasted three days with horrific contractions and a last-minute-Cesarian that ravaged me physically and emotionally- , I ended up battling severe fatigue, severe insomnia, and a rapid deterioration of my health in general all by myself!

How ironic that during these crucial times when I needed to be at the peak of my performance as a new mom,
I had found myself at the lowest of my vitality & vigor! And I was so young, just 31!

So my story of ill-health began after giving birth to my son. It started with that anemia, then with no sleep; it got worse with the physical and emotional demands of breastfeeding several times at night; and due to not being able to rest at any time of the day or night, burnout ensued. My ignorance and the absence of professional support made everything worse for me very quickly. Doctors insisted on putting me on anti-depressants -but I wasn't depressed! - and no doctor ever mentioned to me the importance of modifying and enriching my diet and taking some key nutrients to support adrenal function and restorative sleep.

During my years of severe burnout I was a living ghost, unrecognizable as you would see me today. I was pale, had dark circles under my eyes, had constantly sweaty hands, heart palpitations, could barely open my eyes to see around me, found it difficult to breathe, and felt miserably sad and hopeless. I also put on a lot of weight and couldn't get rid of the excess or feel the energy to exercise.

It was then that I came across a holistic doctor for the first time in my life who explained to me why I was so ill and put me on a healing treatment based on natural healing foods and natural supplements that literally brought me back from the dead in just a few months!

In a matter of weeks I started seeing good improvement.
In a matter of months I was feeling normal again.
In a matter of a short time in comparison to other conventional treatments that I had tried before, I got my life and my health back!


We found out that I metabolize carbs very quickly. This is called being a "fast oxidizer". So I abandoned a diet that I thought was super healthy and adopted a high-fat-high-protein diet with very little carbs in it. In less than 3 months my hypoglycemia and insulin resistance were gone! For ever! And I lost all the weight that I needed to lose. 


By eating animal protein and taking minerals and essential fats my sleep was restored and I started resting properly and sufficiently.

By removing gluten from my diet I lost the extra weight and felt energized and revitalized like in my teenage years again.


I now exercise vigorously daily from Mondays to Saturdays and lift heavy at the gym.  I also teach power yoga three to four times per week on top of that. I am very active and my energy levels tend to be quite high! Now in my mid forties nothing ever hurts in my body. I don't know what a headache is; I never take any pain-killers; and I feel absolutely amazing all the time!


Today, I have become a natural medicine practitioner myself and my passion is to help people like you to recover optimum health & wellness with the power of nature and the wonders of functional medicine!

I hope that my story will inspire you to try new routes of healing that can literally change your life in wonderful new ways. 


In Optimum health,

My statement...


I'm aware of the increase in complex, chronic diseases such as diabetes, heart disease, sleep problems, hypertension, mental illness, autoimmune disorders, obesity, cancer, etc. My training as a nutritional therapist, a functional medicine practitioner, and a yogi has taught me to focus on identifying the underlying causes of disease and to look for interactions between environmental, nutritional, genetic, and lifestyle factors.

My approach is 100% holistic and personalised - I seek to promote health & vitality in each one of my clients by integrating the best of functional diagnostic tools with prevention through combinations of botanical agents, supplements, therapeutic diets, detoxification, exercise, and stress management, rather than concentrating my efforts on just symptom relief.

On 25th May 2018 the European General Data Protection Regulations (GDPR) superseded the Data Protection Act 1998.

GDPR updated data protection rules to be more appropriate to the modern digital age.

GDPR gives more rights to individuals in the processing of their personal data which means that individuals can request access, corrections and removal of their personal information in ways that weren’t available before. There is also a focus on transparency with privacy notices detailing how data will be used and a requirement for procedures documenting exactly how data will be processed and secured.

The new GDPR requires clearer evidence of consent from individuals and some methods of recording consent will no longer be valid. Additionally, GDPR gives greater powers to the ICO (Informat
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British Association for Nutrition & Applied Nutritional Therapy

Nutritional Therapy 

I'm a nutritional therapist with a three-year diploma from The London College of Naturopathic Medicine  (CNM).

Practitioners of nutritional therapy, like myself, use a variety of tools to assess and identify any nutritional imbalances that could be causing problems in an individual's body, as well as to understand how they might contribute to their symptoms and/or health concerns.

By using this approach, nutritional therapists can work with you to look at nutritional imbalances and help support your body towards maintaining health. Nutritional therapy is ideal for individuals with chronic conditions, as well as those looking for support to increase their health and enhance their wellbeing.

In nutritional therapy we not just focus on nutritional deficiencies, but also on detoxification of organs and tissues, on rebalancing the microbiome (healthy flora), on addressing inflammation with natural agents, on supporting healthy organ function or hormonal balance, etc. 


You can expect from me personalised nutrition and lifestyle programmes that are tailored for you as a unique individual.


Functional Diagnostic Lab Tests

Each client that I meet is genetically unique and has unique predispositions to biochemical imbalances (or what conventional medicine calls "diseases"). However, although we may well present "predispositions" to these imbalances,  a new standard of care that is based on recent molecular research & epigenetics recognizes the undeniable fact that environmental and nutritional factors interact with our genes to produce either optimum health or illness.  

As a nutritional therapist and functional medicine practitioner, I use laboratory evaluations that help me understand the etiology of my clients' health problems thanks to a detailed lab analysis of their unique biochemical, toxicological and nutritional status, at any given time.

These evaluations not only explore underlying biochemical glitches contributing to illness and disease in an individual, but also they offer the option to be undertaken by healthy people wishing to identify correctable abnormalities in their systems, that if left alone otherwise, could create health problems in the future. 

I work in close collaboration with some of the best laboratories in the UK offering a wide range of advanced, cutting-edge functional diagnostic tests, genomic tests, and biochemical reports

Please click the button below to see the list of laboratory tests that I can order for you once we have discussed your individual case during your first consultation.

Functional Medicine

I'm a nutritional therapist with a three-year diploma from The London College of Naturopathic Medicine  (CNM). I'm also a functional medicine practitioner, trained with The University of Functional Medicine

Functional medicine is -as described by the Institute For Functional Medicine- "a dynamic approach to assessing, preventing, and treating complex chronic disease. Functional medicine acknowledges  that chronic disease is almost always preceded by a lengthy period of declining function in one or more of the body's systems. Returning patients to health requires reversing (or substantially improving) the specific dysfunctions that have contributed to the disease state. Those dysfunctions are, for each of us, the result of lifelong interactions among our environment, our lifestyle, and our genetic predispositions. 

Functional medicine practitioners reason that extensive scientific evidence strongly indicates that impaired physiological processes, if not corrected, lead to significant clinical imbalances in essential body systems.

Functional medicine clinicians focus on restoring balance to the dysfunctional systems by strengthening the fundamental physiological processes that underlie them, and by adjusting the environmental inputs that nurture or impair them.”

Your health is your most precious treasure. Without it, it's difficult to sail with ease & confidence through the many challenges and the many joys of life.

Ageing is no longer a valid excuse for us to allow our precious body to weaken and deteriorate with time; neither are most medical diagnosis of degenerative disease or the so-called "inherited" disorders.

It is possible to reach optimal health -at least a state of optimal health that suits you personally and that you have not experienced before or at least not in many years since you developed your illness- , and to feel & look vibrant and radiant at all ages!

If you have tried other medical routes already to address your health issues with rather disappointing results, the option of functional medicine is now available to you and I am here to guide you through this exciting journey back to the best version of you again.


Are you ready...? If yes, get in touch for an initial chat.


In optimum health,


Tatiana Mercier

Be part of the functional medicine revolution!

If you believe that nature is more powerful than anything and are interested in trying innovative and scientific -yet holistic- ways to improve your health, please get in touch! I'll be delighted to help you!

"Meta-analyses showed that flavonoids have a promising role in improving visual function in patients with glaucoma and ocular hypertension (OHT), and appear to play a part in both improving and slowing the progression of visual field loss".


-Graefes Arch Clin Exp Ophthalmol. 2015 Sep 4. Epub 2015 Sep 4. PMID: 26340868

"Animal studies show that holy basil helps the body maintain homeostasis of the stress hormone cortisol.1 It rebalances mood-associated neurotransmitters in the brain—specifically ones that can produce feelings of hopelessness, which is a key component of stress-induced depression."2

1- Phytother Res. 2016;30(5):805-14

2-Indian J Med Res. 2012;135(4):548-54




"EGCG (from green tea extract) regulates genes involved in fat oxidation and storage, as well as genes involved in insulin signaling and glucose metabolism."

-Planta Med. 2004 Nov;70(11)


"Effect of unsaponifiable extracts of avocado and soybean (Piasclédine) on the collagenolytic action of cultures of human rheumatoid synoviocytes and rabbit articular chondrocytes treated with interleukin-1."

- Rev Rhum Mal Osteoartic. 1991 Apr;58(4):241-5. PMID: 1647544

"This meta-analysis showed a significant effect of supplementation with Spirulina in reducing plasma concentrations of total cholesterol, LDL-C, triglycerides and elevating those of HDL-C."

- Clin Nutr. 2015 Sep 25. Epub 2015 Sep 25. PMID: 26433766

"Supplementation with olive leaf polyphenols for 12 weeks significantly improved insulin sensitivity and pancreaticβ-cell secretory capacity in overweight middle-aged men at risk of developing the metabolic syndrome."

- Liggins Institute, University of Auckland, Auckland, New Zealand. Dec 31, 2012


"A coconut extra virgin oil-rich diet increases HDL cholesterol and decreases waist circumference and body mass in coronary artery disease patients."

- Nutr Hosp. 2015 ;32(5):2144-52. Epub 2015 Nov 1. PMID: 26545671

"Lycopene, the predominant carotenoid in tomatoes and tomato-based foods, is reported to protect against various cancers, especially prostate cancer. 

Cell growth was inhibited 20% at 0.2 microM lycopene and 40% at 50 microM lycopene after a 24-hr incubation. In the Comet assay, lycopene-treated cells showed less DNA damage than did placebo-treated cells. The inhibition of Hep3B cell growth in this study demonstrates the antitumor properties of lycopene."

- Biofactors. 2005 ;23(3):129-39. PMID: 16410635

"Accumulating evidence indicates that abdominal adiposity is positively related to cardiovascular disease (CVD) risk and some other diseases independently of overall adiposity. However, the association of premature death resulting from these diseases with abdominal adiposity has not been widely studied, and findings are inconsistent. In a prospective cohort study of 44,636 women in the Nurses' Health Study, associations of abdominal adiposity with all-cause and cause-specific mortality were examined. During 16 years of follow-up, 3507 deaths were identified, including 751 cardiovascular deaths and 1748 cancer deaths. After adjustment for body mass index and potential confounders, the relative risks across the lowest to the highest waist circumference quintiles were 1.00, 1.11, 1.17, 1.31, and 1.79 (95% confidence interval [CI], 1.47 to 1.98) for all-cause mortality; 1.00, 1.04, 1.04, 1.28, and 1.99 (95% CI, 1.44 to 2.73) for CVD mortality; and 1.00, 1.18, 1.20, 1.34, and 1.63 (95% CI, 1.32 to 2.01) for cancer mortality (all P<0.001 for trend). Among normal-weight women (body mass index, 18.5 to<25 kg/m(2)), abdominal obesity was significantly associated with elevated CVD mortality: Relative risk associated with waist circumference>or = 88 cm was 3.02 (95% CI, 1.31 to 6.99) and for waist-to-hip ratio>0.88 was 3.45 (95% CI, 2.02 to 6.92). After adjustment for waist circumference, hip circumference was significantly and inversely associated with CVD mortality."

-Circulation. 2008 Apr 1;117(13):1658-67. doi: 10.1161/CIRCULATIONAHA.107.739714. Epub 2008 Mar 24.

"Major changes in self-reported eating behaviors included eating only when experiencing true physiological hunger and stopping when sensing a feeling of fullness. Self-efficacy for these behaviors was reported to be enhanced by observing weight loss for themselves or others. Support from other group members, the simplicity of the program, and spiritual benefits through prayer and scripture reading were also reported to enhance confidence. Women indicated that they relied on an internal locus of control based on a sense of self-discipline.


Traditional means to enhance self-efficacy were important for all women; however, for some women, spirituality was also an important aspect of adhering to program principles."

- J Nutr Educ Behav. 2004 Jan-Feb;36(1):13-5.

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