Which vitamins do you actually need - and how do you find out?

 If you have ever stood in front of a shelf of supplements and genuinely not known where to start, you are not alone. Most people either take a generic multivitamin and hope for the best, or pick vitamins based on what they have seen advertised, what a friend recommended, or what happened to be on offer.

Neither approach is built around what your body actually needs.

The honest answer to the question 'which vitamins should I take?' is that it depends. It depends on whether you are getting enough of specific vitamins from your diet in the first place -- which is harder to know than most people realise. It depends on how your body absorbs what you do eat, because two people can consume the same foods and end up with very different nutrient status.

It depends on your lifestyle - how much sun exposure you get, whether you eat animal products, how varied your diet is week to week. And it depends on something most people have never been told about at all: what your genetics say about how your body processes particular vitamins and minerals at a biological level.

The frustrating part is that most of the information available to help people answer this question is generic. It describes what an average person needs to avoid deficiency - not what you, specifically, need to function well. And that gap between general guidance and personal need is where a lot of people quietly get it wrong, either taking things they do not need or missing things that would actually make a difference.

This article explains why the question is harder than it looks, why the answer matters more than most people realise, and how to get a clearer picture of which vitamins are actually worth paying attention to for your body specifically.

Why it is genuinely difficult to know which vitamins you need

This is not a failure of effort or attention. There are structural reasons why most people do not have a clear picture of their micronutrient needs - and they have nothing to do with how much you care about your health.

The guidelines were not designed to tell you what you personally need

The Dietary Reference Values that underpin most UK nutritional guidance were established to prevent deficiency at a population level. They describe the intake required to meet the needs of most people in a given group - not the intake optimal for any specific individual.

This means the recommended daily amounts you see on supplement labels and food packaging are population averages. They represent a sensible floor for most people. But they were never designed to tell you how much vitamin D your body specifically needs, or whether your iron intake is adequate given how efficiently - or inefficiently - your particular biology absorbs it.

The gap between population guidance and personal need is real, and it is wider for some people than others. Understanding that gap requires information that generic guidelines simply cannot provide.

The micronutrient content of food is less reliable than most people think

When you eat a portion of spinach or a piece of salmon, the amount of vitamins and minerals it actually delivers to your body depends on more factors than most people realise.

Soil quality affects the mineral content of vegetables - and intensive farming practices have changed the mineral density of many crops compared to historical baselines. Food processing strips or degrades certain vitamins - particularly water-soluble ones like vitamin C and B vitamins. Storage time, cooking methods, and even the variety of a crop affect what survives to the point of absorption.

The nutritional databases that food labels and tracking apps draw from are often based on average figures that may not reflect the actual content of the food in front of you. This does not mean that eating well does not matter - it clearly does. But it does mean that assuming you are hitting your micronutrient targets because your diet looks good on paper is not always a reliable conclusion.

Deficiency symptoms are vague and easy to miss

Most micronutrient deficiencies do not announce themselves clearly. The symptoms - tiredness, low mood, poor sleep, frequent colds, slow recovery, difficulty concentrating - are the same symptoms that get attributed to being busy, not sleeping enough, or just getting older. Without a specific reason to investigate, most people never connect these experiences to their micronutrient picture.

This is compounded by the fact that subclinical deficiency - where levels are low but not low enough to show clear clinical signs - is much more common than outright deficiency, and much less likely to be picked up or investigated. You can have consistently low vitamin D, persistently depleted iron stores, or a longstanding B12 issue without ever receiving a diagnosis, because the symptoms are too general and too easy to explain away.

The deficiency gap - more common in the UK than most people realise

Micronutrient deficiency is not a problem confined to parts of the world with limited food access. In the UK, with its abundant food supply, deficiencies remain surprisingly widespread - and often go unrecognised.

Vitamin D is perhaps the most striking example. The UK government already recommends that all adults take a daily vitamin D supplement during autumn and winter - an acknowledgement that for a significant proportion of the population, diet and sun exposure alone are not sufficient to maintain adequate levels through much of the year. Vitamin D deficiency is one of the most common nutritional issues in the UK, with research suggesting that around one in five adults has low vitamin D levels.

Iron deficiency affects a significant proportion of women in the UK, particularly those of reproductive age. Many cases go undiagnosed because symptoms are attributed to other causes before a blood test is considered. B12 deficiency is a growing concern - particularly relevant for people eating plant-based or vegetarian diets, since B12 is found almost exclusively in animal products. And iodine - essential for thyroid function and largely obtained through dairy and fish - is increasingly flagged as a concern in a population moving away from these food sources.

None of this is cause for alarm. But it is a useful reminder that assuming your micronutrient needs are being met simply because you eat a broadly healthy diet is not always a safe assumption. And it is a strong argument for understanding your personal picture rather than relying on the general one.

Signs your micronutrient picture might need attention

Micronutrient deficiencies rarely announce themselves with obvious, specific symptoms. More often they present as a background hum of feeling not quite right - the kind of thing that is easy to dismiss as stress, age, or a busy life.

These are some of the most common signals that your micronutrient picture might be worth looking at more closely. None of them is diagnostic - they can have many causes - but they are the experiences most frequently associated with nutritional gaps when other explanations have been ruled out.

Why vitamins matter more than most people realise

Vitamins are not optional extras. They are the micronutrients your body depends on to perform the functions that determine how you feel, think, sleep, and recover every day. They do not provide energy directly - that is the job of macronutrients - but they make the processes that generate and use energy possible.

Understanding which vitamins support which functions makes the abstract concrete. These are not just numbers on a supplement label - they are the nutritional inputs your body is using right now.

Vitamins do not work in isolation

One of the most important things to understand about micronutrients is that they interact with each other in ways that significantly affect how useful they are to your body. Taking a single supplement in isolation, without understanding how it works alongside other nutrients, can sometimes mean it is far less effective than you expect.

Understanding these interactions matters because it shifts the focus from individual nutrients to the overall pattern of your diet - which is a more accurate and more useful way of thinking about micronutrient nutrition than fixating on any single vitamin. 

Why everyone needs different vitamins

Here is the part that most mainstream nutrition advice leaves out entirely. Two people can eat identical diets and end up with very different micronutrient status - not because of differences in lifestyle or food quality, but because of differences in how their bodies absorb and process specific vitamins and minerals at a biological level.

This is where genetics enters the picture. Specific variants in your DNA influence how efficiently your body converts, absorbs, and utilises particular nutrients. These are not rare or unusual variants - many of them are extremely common. What varies is which combination you carry, and what that means for your personal micronutrient picture.

A few examples that illustrate how significant this variation can be:

The supplement trap - why taking more is not always the answer

The global supplement industry is worth hundreds of billions of pounds annually. It is built, in large part, on the idea that most people are not getting enough of what they need from food - and that the solution is to supplement broadly and regularly.

The reality is more nuanced. For most people eating a reasonably varied diet, most vitamins are present in adequate amounts most of the time. The supplements most likely to be genuinely necessary are the ones where dietary sources are genuinely limited - vitamin D through the darker months in the UK being the clearest example - or where specific dietary choices create a gap, such as B12 for people eating plant-based diets.

The more important point is this: taking a supplement without understanding whether you actually need it, and whether your body is absorbing it effectively, means you are guessing. And there is a specific way in which that guessing can be misleading.

If you have a genetic variant that affects how efficiently you absorb or convert a specific vitamin, taking a standard supplement may not address the underlying issue. Someone with an MTHFR variant affecting folate conversion may take standard folic acid and see limited benefit - because the conversion step that their variant affects means standard folic acid is less useful to them than methylfolate. Someone with variants affecting vitamin D receptor function may supplement with standard doses and still not achieve adequate active vitamin D levels.

Understanding your genetic profile does not tell you exactly which supplements to take. But it gives you a meaningfully better starting point than choosing based on what is on sale, what a friend recommends, or what happens to be marketed most heavily.‍

The food first principle - and why dietary diversity is the foundation

Before thinking about which vitamins to supplement, the most effective starting point for most people is understanding how varied their diet actually is.

Dietary diversity - eating a wide range of foods across different food groups and colour groups - is one of the most consistently supported principles in nutritional science. A varied diet is the most reliable way to ensure broad micronutrient coverage, because different foods provide different combinations of vitamins and minerals that work together in ways supplements cannot fully replicate.

In practice, most people eat a more limited range of foods than they realise. Research on dietary diversity consistently finds that the average adult eats from a relatively narrow repertoire of ingredients - often the same foods in rotation - which creates predictable gaps in specific nutrients. Expanding dietary variety is not about eating expensive or unusual foods. It is about deliberately including a broader range of vegetables, proteins, whole grains, legumes, and healthy fats across the week.

The Eat the Rainbow principle - eating from a variety of colour groups - is a practical shorthand for this. Different colours in fruit and vegetables correspond broadly to different phytonutrients and micronutrient profiles. Red foods, orange foods, green foods, purple foods, white foods - each colour group brings something different. Covering all of them regularly means covering a much broader nutritional base than a diet built around the same few vegetables.

How Boone helps you understand your personal micronutrient picture

Boone was built around a specific observation: people are all different, and yet the nutritional guidance most people receive treats everyone as though they are the same. The micronutrient section of the Boone report is where that observation becomes most practically useful.

Boone analyses your genetic profile across 14 vitamins and minerals - B vitamins (B2, B6, B9, and B12), calcium, choline, iron, sodium, vitamin A, vitamin C, vitamin D, vitamin E, and vitamin K. For each one, the app shows your genetic result, explains what it means in plain language, identifies the genes involved, and gives you clear guidance on which foods to prioritise and which to be more mindful of.

But the genetic report is only the starting point. What makes Boone different is that it connects your micronutrient profile to the food you actually eat.

Boone also shows your micro nutrition scores across five key health areas - Sleep, Heart health, Brain and mood, Energy, and Immunity - each explained by the specific nutritional reasons behind it. These scores are not generic wellness ratings. They are a direct expression of what your micronutrient picture means for how your body actually functions day to day, personalised to your genetic profile and connected to what you have actually eaten.

And based on your genetic profile and your actual micro nutrition scores, Boone generates personalised food recommendations - specific foods that address your particular gaps, organised by biggest impact, worth adding this week, and already working hard for you. Every recommendation can be added directly to a shopping list from within the app.

This is what understanding your micronutrient picture actually looks like in practice. Not a generic supplement recommendation. A personal picture of which vitamins matter most for you - connected to the food you eat every day.

Stop guessing. Start understanding.

The question 'which vitamins should I take?' is a reasonable one. But it is the wrong starting point for most people. The better questions are: which vitamins does my body specifically need more of? Which ones am I absorbing effectively from the food I eat? And which ones am I taking because someone told me to, rather than because I have any real evidence they are relevant to me?

The honest answer to all three is that most people do not know. Not because they have not tried to find out - but because the information available to them has been generic, built around population averages that were never designed to tell any individual what they personally need.

Understanding your micronutrient picture starts with food - eating a varied, whole-food diet that covers a broad range of food groups and colour groups. It is informed by knowing which deficiencies are common and why. It is sharpened by understanding how vitamins interact with each other and why taking isolated supplements without that context is often less effective than it seems.

And it becomes genuinely personal when you understand how your genetics shape the way your body absorbs and processes the vitamins and minerals in the food you eat. Not because genetics is the whole answer - it is not - but because it is the part of the picture that generic advice has never been able to give you.

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