Multivitamin supplements: are they effective?

Raise your hand if you have never taken a multivitamin supplement. I bet most of us have. I have. So, there must be a reason we all take them at some point, they must be useful. Are they?

The JAMA recently published the results of a cohort study of over 390,000 healthy American adults (Multivitamin Use and Mortality Risk in 3 Prospective US Cohorts). The study led by researchers at the National Institutes of Health’s National Cancer Institute analysed 27 years of participants data, looking at the association between mortality and self reported daily multivitamin intake. Overall, half of the population studied consumed daily multivitamins (similarly, nearly half of British adults do).

The results confirm that the intake of such supplements has no benefits in terms of longevity. There was no difference in mortality from cancer, heart disease and cerebrovascular diseases between those taking multivitamins and the others. (In fact, the former were very marginally more likely to die during the study period…).

The unregulated supplement industry is worth tens of billions, and many so called health experts and social media influencers try to convince people that they need supplements to be healthier, stronger, fitter. However, no scientific evidence support these claims. Multivitamins cannot replace a healthy diet, and paying for vitamins/minerals is essentially paying for expensive urine.

A few reminders:
– if you have a diagnosed deficiency, are pregnant or trying to conceive, or elderly, you are not a « healthy adult » 😉
– vitamin D supplements are always recommended during the winter months
– always check with your GP before taking OTC supplements if you take medication
– always consult with your GP if your health deteriorates.


Is personalised better?

Quite a few companies and individuals (with and without qualifications…) now sell personalised nutrition (PN) packages, based on your « unique metabolism and needs« . To assess these, they will first sell you kits to measure parameters such as glycemia, vitamin and mineral levels (iron, B12, D etc), hormone levels (in particular thyroid hormones), blood fats (cholesterol, triglycerides…), gut bacteria and even your genetics. They will also ask you to fill in questionnaires about your dietary habits, lifestyle, general health status (are you tired?) and phenotype (body type, skin colour).

Holzapfel & Drabsch (2019)

They will provide you with your results and their interpretation, and issue « tailored » dietary and lifestyle recommendations: eat more of this, less of that, move more. But does the personalised advice outperform general guidelines? NO.

Several studies have shown that PN does not do any better than general public health advice in healthy adults. In particular you can check the Food4Me European study and Food4Me RCT, The Personal Diet Study, Ben-Yacov et al, and even PREDICT 1 Study by Zoe. The magnitude of difference vs general advice is negligible, and linked to changes recommended in the general guidelines. At 6 month follow-up, most differences disappear. No additional benefits are shown with the addition of phenotype and genotype data. Furthermore, some of these studies are flawed: what is effective on an outcome is determined before the intervention, labelled as « personalised », and participants are told to do what we know will work: the benefit was therefore expected to occur.

The actual contribution of PN is negligible and of questionable relevance. If you are healthy, save your money and follow the general dietary guidelines to stay healthy. 😉

For the UK: the Eatwell Guide
Pour la France: Manger Bouger
Per l’Italia: Mangia Sano

If you wish to improve your diet or achieve a specific goal, work with a dietitian who will assess your needs and objectives, provide 1 to 1 coaching and support for lasting change.


From SAD to glad, how to beat the winter blues

Today I am writing about Seasonal Affection Disorder (SAD) and how to manage it. SAD (what great acronym!) is a transient depression, typically happening during winter months (there is however summer-onset SAD too) when there is less natural sunlight and shorter daylight hours. Since I have lived in London, I have always struggled with it. Now are the shorter days in the year, the weather is grey, rainy and the temperatures unpleasantly mild. It seems never ending…

SAD facts
The prevalence of SAD varies depending on geographical locations and other factors. It is estimated that up to 10% of the population suffers from SAD, and it is more prevalent in women. It is also more widespread in those who had depression in the past, suffer from mental health disorder or have a family history of SAD. Interestingly, it is more common in people born in Spring and Summer.

SAD symptoms and mechanism
SAD usually manifests as low mood, decreased pleasure and increased irritability, lethargy, tiredness, weight gain…
The physiopathology of SAD is not yet completely clear, hormonal dysregulation and low vitamin D are likely involved.

How to fight SAD?
You can combine various strategies if you suffer from SAD.

  • Light therapy: Daily early morning exposure to bright light really helps with SAD. You can buy these devices online, aim for at least 10,000lux.
  • The alternative, and for me a must, is to spend time outdoors, particularly in the morning. Walk to your bakery or coffee place, sweep the leaves, walk the dog… This naturally increases your exposure to daylight, which is effective even in the cloudiest weather.
  • Interestingly, people suffering from SAD show different dietary habits, such as more snacking and more abundant dinners. However, no nutrition intervention has been proven efficient in managing SAD yet. Radically changing your diet when you are struggling is never a good idea, but if you want to reduce snacking, increase wholegrains and fibre rich food for better satiety, and lean protein for easier digestion.
    Make sure you get enough vitamin D and limit alcohol.
  • Physical activity helps release « good mood » hormones that will help you feel better. Again, no need to be extravagant, a 15-30min yoga or weight session, a brisk walk in the neighbourhood will do the job, even more so if share it with a friend.
  • Social connections is indeed one of the easiest way to increase happiness. So for your own well being, be (selfishly) kind to others 🙂
  • You can try mindfulness and relaxation if you like this sort of things. Personally, it makes me worse.
  • Anything that helps decrease your stress levels will help, as well as having things to look forward to.
  • Last, but absolutely necessary, seek professional help if you feel that SAD has too big an impact on your life.

My dear readers, if you suffer from SAD, soon the days will get longer and the skies brighter. Close your eyes and imagine your dream place. Mine is anywhere by the ocean, on a sunny day… Much love x



Fearmongering refers to using fear to influence the opinions, beliefs, or actions of others. It often involves spreading exaggerated or misleading information, sensationalising situations, or highlighting potential dangers in a way that evokes strong emotions of fear, anxiety, or panic.
Fearmongering can be employed for various reasons, such as gaining support for a particular agenda, promoting a certain viewpoint, or manipulating public opinion. It can be seen in politics, media, advertising, and other spheres where the intention is to manipulate perceptions and behaviours through instilling fear.

Fearmongering is widespread in nutrition, where people often use it to sell products (useless but expensive food supplements) and services (fad diets that will mostly slim your wallet). These people have a very loud voice and huge influence, their opinions can be watched on Netflix (typical examples include the Game Changers, Seaspiracy and most food related documentaries), their « quick and easy diets » to lose weight seduce thousands on social media. It is in fact very hard to resist the pseudoscience and numerous magical claims that circulate online.

Here is a short list of typical fearmongering techniques in nutrition to help you identify them:

  • Labelling foods or food groups as « toxic » without any evidence to back this up. A typical example is sugar, some people make a lot of money demonising glucose. They will refer to in-vitro or animal studies to support their extraordinary claims, and present them as a scientific truth.
  • Claiming some foods cause cancer, again is totally wrong, and sugar is a typical example of this.
  • Asking to avoid an ingredient if you can’t pronounce its name. About this I share this Wikipedia article about the dihydrogen monoxide parody. I personally find it quite funny, and invite you to play this trick on your friends.
  • Banning foods has no scientific grounds, unless you are allergic to it.
  • Putting foods in categories: healthy/unhealthy, good/bad (as if food had a moral value), etc. Food is meant to be enjoyed, some with moderation, but restricting food on the basis it it « bad/harmful/toxic » often leads to obsessing over it and can trigger eating disorders.
  • Sciency buzzwords such as « clinically tested », « medical grade », « special formula » are meaningless, this is marketing not science.
  • Can you think of anything else?

A difficulty is that providing nutrition advice is poorly regulated in many countries. You can declare yourself a diet expert and sell meal plans to anyone with no or little training. I am sure you can think of a few celebrities recommending unachievable and potentially harmful diets. And even people with credentials may use fearmongering to sell you something.

How to navigate those shallow waters?
First learn to recognise fearmongering, it will also help you beyond nutrition (remember the Covid vaccines!). Then find reliable sources of information such as registered dietitians and nutritionists. Be mindful that a blue mark or huge following is not an indication of quality nutrition advice, neither is a medical degree. Indeed, most GPs/MDs have little knowledge in diet and nutrition because this is a very very small part of their training. Your own GP remains, however, the first person you need to contact if you have medical concerns. Likewise, a competent dietitian or nutritionist will ask you to see a GP if they have any concern about your health.

In a future article I will share a few diets myths to stay away from.


Shining a light on winter health: vitamin D supplementation

As the days become shorter and the temperature drops, the winter season brings about a delightful change in scenery. However, it also brings with it a reduction in our exposure to sunlight, which can have a significant impact on our vitamin D levels. In this article, I want to shed light on the importance of vitamin D supplementation during the winter months and provide guidance on the recommended dosage.

Why Vitamin D in winter?

Vitamin D is often referred to as the « sunshine vitamin » because our skin can produce it when exposed to sunlight. However, during the winter, many people experience a decrease in outdoor activities and sunlight exposure due to colder weather and reduced daylight hours. This reduction in sun exposure can lead to a decline in our natural vitamin D synthesis, making supplementation a valuable option. Here are the reasons why you should consider taking a vitamin D supplement during this time:

  1. Maintaining immune health: Vitamin D plays a crucial role in supporting a robust immune system. Adequate levels of vitamin D are associated with reduced risk of infections and a more efficient immune response. This becomes especially important during the winter months when colds and flu are more prevalent.
  2. Bone health: Vitamin D is essential for the absorption of calcium, which is vital for strong bones and teeth. Inadequate vitamin D levels can lead to a higher risk of bone-related issues such as osteoporosis and fractures, which may be exacerbated in the winter when outdoor physical activity decreases.
  3. Mood and mental health: Some research suggests that vitamin D may play a role in mood regulation. Seasonal affective disorder (SAD) is a type of depression that typically occurs in the winter months, and vitamin D supplementation has been explored as a potential way to alleviate its symptoms.
  4. Vitamin D is also involved in other physiological mechanisms such as blood clotting, hormone signalling, nerve transmission and muscle contraction.

Recommended dosage

I refer here to the recommendations of the NHS, they candiffer in other countries (in France, there is no public health recommendation for supplementation for example):

  • « Babies up to the age of 1 year need 8.5 to 10 micrograms of vitamin D a day.
  • Children from the age of 1 year and adults need 10 micrograms of vitamin D a day. This includes pregnant and breastfeeding women, and people at risk of vitamin D deficiency. »

Vitamin D supplements should be used as a complement to a healthy diet, not as a replacement. You can also increase your vitamin D intake through dietary sources: oily fish (salmon, sardines, herring and mackerel), mushrooms, liver, egg yolks, and fortified foods – such as some milks and fat spreads, and breakfast cereals.

But as the winter season limits our natural sunlight exposure, considering a vitamin D supplement can help ensure you maintain optimal vitamin D levels and overall well-being during the colder months.


The role of fats in your diet and health

Lipids often get a bad reputation, but they are an essential part of a healthy diet and play crucial roles in human physiology and metabolism. In this blog post, I explore the functions and roles of fats in your body, shedding light on why you shouldn’t fear them but rather embrace the right kinds of fats for overall well-being.

1. Energy source: Fats are an efficient source of energy. They provide 9 calories/gram compared to 4 calories for carbohydrates or protein. When your body needs energy, it can break down fats, releasing a steady supply of fuel.

2. Nutrient absorption: Fat-soluble vitamins (A, D, E, and K) require dietary fats for absorption. Fats help transport these vitamins from the digestive tract into the bloodstream, where they can be utilised by the body.

3. Cell structure and function: Fats are essential components of cell membranes. They help maintain the integrity and flexibility of cell structures, allowing cells to function properly.

4. Brain health: The brain is primarily composed of fat, and it requires dietary fats, especially omega-3 fatty acids, for optimal function. Omega-3s are associated with cognitive function, memory, and mood regulation.

5. Hormone production: Fats are involved in the synthesis of various hormones, including sex hormones (oestrogen and testosterone) and stress hormones (cortisol). Balanced hormone production is crucial for overall health.

6. Insulation and protection: Subcutaneous fat (the fat beneath your skin) serves as insulation, helping regulate body temperature. It also provides a cushioning layer to protect vital organs.

7. Long-term energy storage: Excess energy from the food you consume is stored as triglycerides in fat cells. When energy intake is reduced (as in fasting or between meals), these stored fats are broken down and released into the bloodstream for energy.

8. Immune function: Fats play a role in the body’s immune response. Omega-3 fatty acids, in particular, have anti-inflammatory properties and can help support the immune system.

9. Skin and hair health: Dietary fats help keep your skin and hair healthy and glowing. They assist in maintaining moisture and skin elasticity.

10. Flavour and satiety: Fats add flavour to foods, making them more enjoyable. They also contribute to a sense of fullness and satiety, helping to control appetite and prevent overeating.

Lipids are not your enemy but essential allies in maintaining a healthy and well-functioning body. However, it’s important to choose the right kinds of fats. Opt for unsaturated fats like those found in avocados, nuts, and olive oil while limiting saturated and trans fats. By incorporating healthy fats into your diet in moderation, you can harness their numerous benefits and promote overall well-being.

Remember, balance is the key to a nutritious and satisfying diet.

For personal advice, please contact me!


Understanding the need to increase protein intake: reasons and considerations

A year ago I published a post on Protein and ageing, where I quickly explained the many roles of proteins in human physiology. Several reasons may lead individuals to increase their protein intake, depending on their specific health goals, lifestyles, and circumstances. Here are some common examples:

  1. Muscle building and strength training: People who engage in regular strength training or resistance exercises often require more protein to support muscle growth and repair. Athletes and bodybuilders may have higher protein needs.
  2. Ageing: As people age, there can be a natural decline in muscle mass and protein metabolism. Older adults may benefit from increased protein intake to maintain muscle mass, strength, and overall health.
  3. Weight management: Protein has a satiating effect and can help control appetite and reduce calorie intake. Including more protein in the diet can be beneficial for weight loss and weight management efforts.
  4. Pregnancy and breastfeeding: Pregnant and lactating women require extra protein to support the growth and development of the fetus or infant. Protein is essential for the formation of tissues and organs in the baby.
  5. Wound healing and surgery: After surgery or injury, the body needs additional protein to repair damaged tissues and promote wound healing. Healthcare providers may recommend increased protein intake during recovery.
  6. Chronic Illnesses: Some medical conditions, such as diabetes, kidney disease, and certain gastrointestinal disorders, may increase protein requirements or alter protein metabolism. Healthcare professionals can provide guidance on individualised protein needs in such cases. Always consult your GP when you consider changing your diet and have a chronic condition.
  7. Vegetarian and vegan diets: Individuals following vegetarian or vegan diets may need to pay closer attention to protein intake to ensure they are getting enough essential amino acids. Plant-based protein sources can be lower in certain amino acids, so variety is key.
  8. Active lifestyles: People with physically demanding jobs or active lifestyles may need more protein to support their energy expenditure and overall health.
  9. Recovery from illness or infection: During illness or infection, the body’s protein needs can increase due to immune system activation and tissue repair. Adequate protein intake can help with a faster recovery.
  10. Malnutrition or undernutrition: Individuals who are malnourished or undernourished, whether due to poverty, food insecurity, or other factors, may need increased protein intake to address nutritional deficiencies.
The different functions of proteins

It’s important to remember that individual protein requirements can vary widely based on age, gender, activity level, health status, and other factors. Consulting with a healthcare provider or a registered dietitian can help determine the appropriate protein intake for specific needs and goals, ensuring a balanced and healthy diet.


Building habits (part 3): essential rules

In the first article, I explained how habits rely on our brain autopilot and support our executive functions. Whatever is your goal, there are key rules when implementing your habits.

1 – Something is better than nothing

To form a new habit, you need to activate your neural networks. It means you need to stimulate them: doing something will, doing nothing won’t. Start small and build on.

2 – Consistency matters the most

When you start working on new habits, your executive brain is still activated and actions are very deliberate. As the new routine is implemented, the autopilot is activated. The more often you repeat the new action, no matter how small, the stronger and the more efficient the autopilot becomes. Eventually the autopilot takes over: the habit is formed.

This has to do with synaptic plasticity, which is as Wikipedia simply puts it « the ability of synapses to strengthen or weaken over time, in response to increases or decreases in their activity ». Repeated actions, over time, become habits. Random actions don’t.

3 – Repeated, « good enough » actions

When trying to form new habits, we sometimes set the bar too high, feel discouraged and can’t be consistent. Reduce your threshold of what is « good enough » to focus on small, achievable and sustainable actions that you can do consistently. This will activate the autopilot and embed the new habit.

In a few words, regular small steps will take you to your objective.

As I started a new job, one of my objectives is to build a routine around publishing articles here. I am aiming for one per week but need to find the right cues (time, place etc).

And you, are you trying to implement a new habit in your life?


Sugar and cancer risk

TL, DR: sugar is not a carcinogenic (cancer-causing) substance.

The idea that sugar fuels cancer cells is a fallacy that unfortunately thrives on the Internet. No studies in people have shown that reducing sugar intake prevents or treats cancer. No studies have shown that eating too much sugar causes cancer.

There is no direct link, and therefore no causality, between sugar and cancer.

All cells, including cancer cells, require energy to survive and grow, this energy is glucose. When we eat sugary foods (simple carbohydrates), glucose gets absorbed straight into the bloodstream ready, for cells to use. When we eat starchy food (complex carbohydrates), like pasta, the digestion process breaks them down into glucose. When there are no carbohydrate in our diet, cells can turn fat and protein into glucose as a last resort, because they need glucose to survive. This means that replacing sugar with other energy sources won’t affect the growth of cancer cells.

Remember that a healthy diet includes carbohydrates, for the energy, fibre, minerals and vitamins that they contain. Avoiding healthy, nutritious foods is not a science-based method to prevent any disease. Avoiding sugar will not prevent cancer, as consuming sugar won’t cause cancer. « Cancer » is a group of different diseases triggered by a huge variety of genetic and lifestyle factors.

The only link between cancer and sugar is indirect: excessive sugar intake can lead to weight gain and increase the risk of obesity and diabetes, which may in turn increase the risk of cancer.


Building habits (part 2): key steps

In the first article I explained how habits support the executive functions of the brain. It is estimated that 40% of our actions rely on habits, this is why building habits that serve your goals is essential. Here are a few tips for that.

Tip 1: Identify the habit

The new habit or routine is the behaviour you want to start or change. This can be exercising, stop adding salt, walking more. I will take the example of my Saturday 8.30am yoga class.

Tip 2: Set reminders

One of the key aspects to forming a new habit is remembering everything you need to remember in order to follow through on your aspiration. Forgetting is easy, as our brains always take the easy way, the way of current habits 😉

In my case, I have 2 reminders for this yoga class: one to remember to book the class, and one popping on my phone 30mins before the class.

Tip 3: Start small

This means being specific, and to think of the when, where, how. My aim was not to go to yoga everyday, but to commit to this one, every Saturday. If you can’t proceed to your chosen habit (class cancelled, preferred food not available etc) , have an alternative so that your brain does not associate the reminder to nothing. My alternative to yoga is running. Anything is better than nothing.

Small actions are the seeds for the habit to grow, they activate your neuronal networks.

Tip 4: Reward yourself

We are wired to seek pleasure. Our brain releases « happiness » chemicals during reward, which help the remodelling of neuronal circuits and new habits to stick. We usually think of extrinsic rewards (money, food, objects) but intrinsic rewards work just as well: this feeling once you finish your run, the calm after yoga, learning a new skill, being more energised etc. Remember that the reward comes from the smallest action towards your goal, so the smallest step towards changing or building a habit is rewarding.

After my yoga class, I feel both relaxed and energised, I am (usually!) satisfied with the progress made, and seeing my teacher is a pleasure in itself.

Tip 5: Repetition

As you repeat an action, the new neuronal circuits reinforce and it starts to require less effort. With time, the action is transferred from executive brain, that requires a lot of mental energy, to the autopilot brain and it becomes easier and almost automatic.

And you, what habit would you like to build to achieve your goals?

My current challenge is to eat less salted butter to decrease my overall salt consumption 🙂