DUTCH Provider Spotlight: Dr. Tamsin Lewis

Dr. Tamsin Lewis Case study:

About Dr. Lewis:

Dr. Tamsin is a medical doctor trained at Kings’ College London. Her medical career began in psychiatry, an interest sparked as it afforded the opportunity to take a detailed history of the patient and really look at the why behind their presenting symptoms. From an early stage, she was interested in the mind-body connection and the interplay between physical and mental health.

Tamsin spent 2 years as an amateur triathlete – competing in age-group competitions – whilst working full time as a doctor ultimately before she had the opportunity to compete at the professional level. Her experience has taught her that triathletes whether amateur or elite place huge demands on their physiology – and it’s difficult within the context of everyday life demands to keep up – and maintain health. Often it is a case of performance at all costs.

The costs being fatigue, sleep disturbance, libido issues, mood disturbances and obsessive behavioral patterns.

Tamsin became intrigued by these factors and how we could objectify them by tracking certain ‘biomarkers. Her standard medical practitioner had no answers for the above issues, other than “take time off”, “eat more” and “perhaps you would benefit from some iron tablets”.

Not convinced by these vague answers, she immersed herself in the research around performance medicine and began to test herself and a growing client base.

Blood Testing only appeared to show part of the picture – and while useful in allowing insights into blood health – it did not allow insights into the adrenal (stress hormone) system or detail about sex hormone levels and the body’s processing of such. All of which are influenced by a demanding schedule. It was Ben Greenfield – a close friend – who turned Tamsin’s attention to the Dutch Test as a comprehensive means of capturing biochemical insights and even better showing us how to manipulate these insights in a way that boosts performance – health and general wellbeing. Tamsin has been using the DUTCH Test with clients since its very first inception – you could say she was an early adopter. It took her a while to get comfortable with the amount of detail provided in the report – but now – having run over 400 tests – She is very comfortable with creating a bespoke lifestyle and nutritional plan based on DUTCH Test data.

Athletic concerns usually fall into these categories below and she has found the DUTCH invaluable tool in shedding light in the context of these testing motivators:

  • Reducing Fatigue
  • Improving sleep quality
  • Improve body composition
  • Reducing injury
  • Enhancing overall performance
  • Optimize mood – motivation

The DUTCH test has been an invaluable tool in working with the athletic population to scratch beneath the surface in uncovering metabolic, endocrine and hormonal imbalances. Providing the ‘why’ which is critical to answering the ‘how’ and more importantly creating a targeted effective protocol moving forwards.


Patient Case Study:

Claire, 37

  • Busy advertising manager with lots of international travel
  • Married and looking to get pregnant, yet has irregular menstrual cycles and has been on the OC Pill for many years.
  • Enjoys sporting events and thus trains 15 hours per week.

Issues wishing to address:

  • Inability to push hard in exercise sessions but could go steady all day
  • Disrupted sleep – waking at 2-4am every night
  • Occasional night sweats – esp. Before period due
  • Concentration and focus reduced at work
  • No ‘zing’ / sex drive
  • Muscle cramps and occasional abdominal cramps
  • Frequently picking up colds, stomach bugs etc
  • Fertility Issues
  • Suggested Tests for a comprehensive Insight:

Fibr Performance Package

= Full Blood Screen + DUTCH Hormone Test + GI map Stool Test.

Tests Revealed:

  • Low Iron Stores (Ferritin)
  • Low Vit D
  • Low Magnesium
  • Low Luteal Phase Progesterone
  • Low DHEA
  • Low Free Testosterone
  • Low Cortisol Production
  • Suboptimal Thyroid Function
  • Adequate Oestrogens and Oestrogen Metabolites
  • Slow Methylation

Results derived:

While busy maintaining her successful career, training religiously, managing family stress; Claire neglected her own health.

She ate more processed food and drink than she realized, slept poorly, and prioritized exercise over relaxing. She spent 10 years “living on adrenaline”, fueled by caffeine, refined sugar and more alcohol than she wanted to admit.

Based on functional lab testing, we did indeed learn Claire had reduced adrenal gland function – low cortisol, and low metabolized cortisol in the context of low DHEA, and progesterone. All inter-related and a result of unsupported lifestyle in the context of a very driven and perfectionist personality. An adaptation by the body to get her to slow down. But who has time to really slow down? – most don’t until they reach rock bottom – and are then forced to claw their way back up out of a longer, darker hole.

Her gut test further revealed a Helicobacter pylori and Klebsiella infection (2 bacterial infections) common when stress has been present for some time lowering gut immunity. Conversations revealed Claire struggled to process emotional stress and felt that she had little control over her life – a sense of overwhelm – which becomes more obvious in individuals with low DHEA. The gut infections were creating yet another layer of stress – think – a system constantly battling to keep the bacteria from multiplying.

We focused on lifestyle changes and treated her gut infection and provided a plan to strengthen the gut’s resilience.

The Sex Hormone Imbalance often improves when the adrenals are better supported by nutritional, supplementary and lifestyle changes. But often in an athletic 30-40’s age group direct bio-similar hormone replacement is indicated – especially if there is pronounced sleep disturbance, irregular menstrual cycles, and mood swings.

We try to boost the body’s own hormonal balance first – but for some – more direct measures are indicated and can have a huge relatively fast impact on how they feel and function.

Claire embraced the challenge of reducing hormone disrupting and methylation reducing chemicals in her life: swapping out her personal care, household cleaning products, and plastics with natural safer alternatives. Every little bit helps.

While following her protocol, Claire committed to taking time to prepare and eat balanced, nutritious meals with lots of healthy fats.

To support Claire’s weak methylation, we increased her intake of leafy greens, beans, fruit, and whole grains to get adequate levels of vitamins B6, betaine, and folate. She included Egg yolks, meat, liver, and oily fish to support dietary sources of choline and vitamin B12.

All important to support adrenals and the nervous system.

She began to enjoy cooking whilst listening to her favorite books on audio, by getting her husband involved and always made extra to place in the freezer or to enjoy for lunch the next day. She and her husband arranged their schedules to take quality time out a few times a week to sauna, attend a local Pilates class or walk in nature.

In addition, she made a point to be in bed by 10:00 P.M. to ensure she received adequate rest and recovery. Claire made her bedroom more conducive to sleep by adapting her bedroom using the Fibr Good Sleep Guidelines.

Although making these lifestyle changes was difficult, she realized that she needed to let some chores slide and rearrange her priorities. Those decisions, followed by smart lifestyle choices day to day, along with follow-up consultations and testing, helped to renew her strength and resolve and put her back on track for a healthy life.

3 months on her personalized protocol involving an adapted exercise routine, targeted supplements, stress reduction exercises, overall toxin reduction and a diet high in good fats helped to normalize Claire’s monthly menstrual cycle and she was able to conceive after 4 months.