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Multi-Vitamin and Mineral Supplements and Autism Ranking: Insufficient/Mixed evidence

Vitamin capsules

Multi-vitamin/mineral supplements (often known in the USA as MVM supplements, multis, multiples or mega-vitamins) contain a combination of vitamins and minerals, and sometimes other ingredients as well.

There are many types of multi-vitamin/mineral supplements in the marketplace. Manufacturers choose which vitamins, minerals, and other ingredients, as well as their amounts, to include in their products.

Some people think that certain individuals on the autism spectrum have a range of nutritional and metabolic problems. These include low levels of nutrients, high levels of oxidative stress (a chemical state within cells that can increase cellular damage) and difficulties with metabolic processes (such as digestion). 

Some people think that these nutritional and metabolic differences may cause some of the core features of autism (such as impaired communication and social difficulties) and related issues (such as challenging behaviours). 

They also think that some of these problems can be overcome by taking multi-vitamin/mineral supplements, often in combination with other therapies such as special diets.

Our Opinion

There is some evidence that certain individuals on the autism spectrum may have nutritional and metabolic problems. However, the number of individuals on the autism spectrum who have these problems is not clear. It is also unclear whether these problems or differences are more common in individuals on the autism spectrum than in other individuals. It is also unknown whether these problems cause or worsen symptoms (of autism or related issues) or arise because of autism, or are completely unrelated to autism. 

There is a very limited amount of low quality evidence (three group studies) on the use of multi-vitamin/mineral supplements as an intervention for people on the autism spectrum.  This is insufficient to determine if multi-vitamin/mineral supplements provide any benefits to people on the autism spectrum beyond the benefits they provide to people who are not on the autism spectrum. 

There is a need for further research into the use of multi-vitamin/mineral supplements for people on the autism spectrum. Specifically there is a need for studies which use robust methodology, for example, large-scale, placebo-controlled, randomised, double-blind trials carried out on several sites. 

That research should also identify which individuals are most likely to benefit from which formulations and dosages; should determine if multi-vitamin/mineral supplements can be used as one of the elements within comprehensive, multi-component, treatment model; should compare multi-vitamin/mineral supplements with other interventions which are designed to achieve similar results, such as special diets.

That research should also identify if multi-vitamin/mineral supplements have any beneficial effects in the medium to long term and in real world settings. It should also involve people on the autism spectrum in the design, development and evaluation of those studies. 

In the meantime, we recommend that if you are taking multi-vitamin/mineral supplements you should follow guidance on their usage from the appropriate organisation in your own country (such as the Food Standards Agency in the UK or the Office of Dietary Supplements in the USA).

Disclaimer

Please read our Disclaimer on Autism Interventions


Audience

According to Bazian (2011), “…nearly a third of people in the UK take some vitamin, mineral or dietary supplement on most days, and about 15% of us report having taken a “high dose” supplement in the last 12 months.”

Healthcare providers recommend that certain specific groups of people should take specific supplements.  For example according to NHS Choices (2016), the Department of Health recommends certain supplements for some groups of people who are at risk of deficiency. These include

  • Folic acid supplements for all women thinking of having a baby or any pregnant women up to week 12 of their pregnancy.
  • Vitamin D supplements for everyone over the age of five (including pregnant and breastfeeding women), particularly between October and March.
  • Supplements containing vitamins A, C and D for all children aged six months to five years old.
  • Supplements if you need them for a medical condition. For example, you may be prescribed iron supplements to treat iron deficiency anaemia.

Some researchers (such as Adams et al, 2011) have suggested that some individuals on the autism spectrum are a specific group of people who are likely to benefit from taking multi-vitamin/mineral supplements because they are likely to have a range of nutritional and metabolic problems.

Aims and Claims

Aims

According to Bazian (2011), “People take supplements for all kinds of reasons, usually relating to their health. They hope these will boost vitality, limit the signs of ageing, extend life, cut the risk of chronic disease such as cancer and treat specific ailments such as arthritis”.

Some people think that many people on the autism spectrum have a range of nutritional and metabolic problems and that those problems can be overcome or reduced by taking dietary supplements. For example Adams et al (2011) concluded  

“The autism group had many statistically significant differences in their nutritional and metabolic status, including biomarkers indicative of vitamin insufficiency, increased oxidative stress, reduced capacity for energy transport, sulfation and detoxification. Several of the biomarker groups were significantly associated with variations in the severity of autism. These nutritional and metabolic differences are generally in agreement with other published results and are likely amenable to nutritional supplementation.”

However not all researchers agree as to whether the nutritional status of people on the autism spectrum is or is not significantly different to non-autistic people. For example, Marí-Bauset et al. (2015) conducted a review of growth and nutritional status in children on the autism spectrum and reported that

“The limited research published on growth and nutritional status has found contradictory results. Nutritional assessment has indicated limited food variety in the ASD population but has not confirmed significant differences with respect to recommended intakes or controls.”

Claims

There have been various claims made for the use of multi-vitamin/mineral supplements as an intervention for people on the autism spectrum. For example,  

  • Adams and Holloway (2004) claimed that multi-vitamin/mineral supplements delivered “… statistically significant improvements in sleep and gastrointestinal problems… “
  • Adams et al (2011) claimed that multi-vitamin/mineral supplements delivered improvements in a range of areas including hyperactivity, tantrumming, repetitive language, as well as overall behaviour. 
  • Mehl-Madrona et al (2010) claimed that multi-vitamin/mineral supplements reduced self-injurious behaviours and improved overall behaviour.    

Key Features

Multi-vitamin/mineral supplements (also known as MVM supplements, multis, multiples and mega-vitamins in the USA) contain a combination of vitamins and minerals, and sometimes other ingredients as well.

There are many types of multi-vitamin/mineral supplements in the marketplace. Manufacturers choose which vitamins, minerals, and other ingredients, as well as their amounts, to include in their products. 

We found a wide range of multi-vitamin/mineral supplements when we did an online search of major UK suppliers on 19 September 2017.  The number of ingredients in these supplements varied from 18 to 36.

Some multi-vitamin/mineral supplements are designed for specific functions.  For example, some supplements are designed to provide more energy, to protect your immune system or to control your weight.

Some multi-vitamin/mineral supplements are designed for specific audiences. For example, multi-vitamin/mineral supplements for older people usually provide more calcium and vitamins D and B12 and less iron than multi-vitamin/mineral supplements for younger adults. Multi-vitamin/mineral supplements for pregnant women often provide vitamin A in the form of beta-carotene.

Some manufacturers claim to have produced multi-vitamin supplements specifically for people on the autism spectrum but the formulations of these vary from one manufacturer to another. For example, the multi-vitamin/mineral supplement used in the study by Adams et al (2011) contained 30 different ingredients including vitamin A, vitamin C, vitamin B6, vitamin B12, calcium, iron, lithium, zinc etc.

Multi-vitamin/mineral supplements are available in a wide range of forms including tablets, capsules, pastilles, powders, liquids and injectable formulations.

Because they come in some many varieties and forms and because they are produced by so many different manufacturers, it is important to check the label to see what each supplement actually contains.

Brands

Multi-vitamin/mineral supplements are sold under a variety of brand names, each of which may come in different strengths and be administered in different ways. 

Dosage/Intensity

The dosage will depend to a certain extent on the characteristics of the specific multi-vitamin/mineral supplement being used (trace elements such as zinc should only be given in very, very small doses) and the characteristics of the individual taking the supplement (children generally need smaller doses than adults).

However, care should be taken not to exceed recommended dosages set by organisations such as the Food Standards Agency or the Medicines and Healthcare Regulatory Agency.  This is because high dosages of some substances can cause problems. For example, according to Bazian (2011), levels of vitamin C above 1,000mg a day can cause abdominal pain and diarrhoea.

Dietary supplements in the UK carry labels denoting the percentage of the RNIs (Reference Nutrient Intakes) contained in the product.

Cost and Time

Cost

The cost of buying a multi-vitamin/mineral supplement depends on a range of factors including the type of supplement, the quantity you buy, the supplier, delivery charges etc.

We found a wide range of suppliers providing multi-vitamin/mineral supplements for a wide range of prices when we did an online search on 19 September 2017. Prices varied from £3.50 to £12.99 for 100 tablets.   

In the UK, it is sometimes possible to obtain free NHS prescriptions for specific dietary supplements if you have certain medical conditions (such as diabetes) or you are a member of an exempt group (such as being under 16 or over 65).  GPs will only normally prescribe supplements if there is a diagnosed deficiency, for example, iron or vitamin D.

Time

Most multi-vitamin/mineral supplements are designed to be taken one or more times a day, often before mealtimes.

The length of treatment depends on a range of factors including the type of supplement and the characteristics of the individual being treated.  For example, Adams (2007) states that the use of multi-vitamin/mineral supplements is “lifelong, although improving diet and healing gut may reduce the need for supplementation.”

However we would strongly recommend that you review your use of dietary supplements on a regular basis with a responsible health professional such as a dietitian, GP or pharmacist. This is because you are likely to experience some harm if you take vitamins in large amounts over long periods of time.

Risks and Safety

Hazards

The quality of multi-vitamin/mineral supplements can vary enormously depending on the specific supplement, the manufacturer, the ingredients and the manufacturing process.  

Although the doses of vitamins and minerals found in most multi-vitamin/mineral supplements are thought to be safe, very high levels can be harmful and you are likely to experience some harm if you take vitamins in large amounts over long periods of time.  For example, there have been several cases (Boyd and Moodambail, 2016; Vyas and White, 2011) of young children on the autism spectrum being admitted to hospital with hypercalcaemia. This is a potentially fatal condition caused by excessive calcium levels which can be brought about by taking excessive amounts of vitamin A and vitamin D. 

For this reason, we suggest that you do not exceed the RNIs(Reference Nutrient Intakes) recommended by the Food Standards Agency in UK or the RDAs (Recommended Dietary Allowances) recommend by the Office of Dietary Supplements in the USA.

The Office of Dietary Supplements (2011) noted that multi-vitamin/mineral supplements with very high levels of vitamin A, beta-carotene and iron should be avoided.

“Taking a basic MVM is unlikely to pose any risks to health. But if you consume fortified foods and drinks (such as cereals or beverages with added vitamins and minerals) or take other dietary supplements, make sure that the MVM you take doesn’t cause your intake of any vitamin or mineral to go above the upper levels. Pay particular attention to the amounts of vitamin A, beta-carotene (which the body can convert to vitamin A), and iron in the MVM. “

Contraindications

There are very few known contraindications (something which makes a particular treatment or procedure potentially inadvisable for a particular group of people) for most multi-vitamin/mineral supplements. However the Office of Dietary Supplements (2011) in the USA noted that some people should avoid multi-vitamin/mineral supplements with very high levels of vitamin A, beta-carotene and iron.

  • “Women who get too much vitamin A during pregnancy can increase the risk of birth defects in their babies. This risk does not apply to beta-carotene, however. Smokers, and perhaps former smokers, should avoid MVMs with large amounts of beta-carotene and vitamin A because these ingredients might increase the risk of developing lung cancer. 
  • Adult men and postmenopausal women should avoid taking MVMs that contain 18 mg or more of iron unless their doctor has told them that they have iron deficiency or inadequacy. When the body takes in much more iron that it can eliminate, the iron can collect in body tissues and organs, such as the liver and heart, and damage them. Iron supplements are a leading cause of poisoning in children under age 6, so keep any products containing iron (such as children’s chewable MVMs or adults’ iron supplements) out of children’s reach.”

The Office of Dietary Supplements also recommended that anyone taking an anticoagulant drug (which reduces blood clotting) such as warfarin should seek medical advice before taking multi-vitamin/mineral supplements that contain vitamin K.

“MVMs with recommended intake levels of nutrients don’t usually interact with medications, with one important exception. If you take medicine to reduce blood clotting, such as warfarin (Coumadin and other brand names), talk to your health care provider before taking any MVM or dietary supplement with vitamin K. Vitamin K lowers the drug’s effectiveness and doctors base the medicine dose partly on the amount of vitamin K you usually consume in foods and supplements.”

If you have concerns about your diet or your child’s diet, you should seek advice from a responsible health professional such as a GP or pharmacist. This may lead to a referral to a dietitian, in particular one with experience of working with individuals on the autism spectrum.

Suppliers and Availability

Suppliers 

Multi-vitamin/mineral supplements are available from a wide range of suppliers including health food stores, chemists and pharmacies, professional health care providers and online stores. 

If you are contemplating taking multi-vitamin/mineral supplements, you should seek advice from a GP, pharmacist or dietitian. The British Dietetic Association has information about qualified dietitians in the UK.

For children and adults who are not eating a varied and sufficient diet, for example, avoiding food groups, or eating a very restricted diet, a dietitian can help by assessing dietary intake and advising on testing and supplementation where necessary. 

All professionals involved with adults and children on the autism spectrum should watch for potential nutritional problems particularly if their diets are restricted. 

Credentials

There are no formal, internationally validated registered qualifications for most people who provide multi-vitamin/mineral supplements.   

However, in the UK, the quality of dietary supplements is regulated by the Medicines and Healthcare Products Regulatory Agency, if they ‘contain a pharmacologically active substance or make medicinal claims (claims to treat or prevent disease, or to interfere with the normal operation of a physiological function of the human body) ...’

In the UK certain supplements are considered to be foods and will therefore be regulated under general food laws by the Food Standards Agency and Department of Health. Others will be regulated as a medicine by the Medicines and Healthcare Regulatory Agency (MHRA).

All herbal medicines placed on the UK market must have a Traditional Herbal Registration (THR) or a marketing authorisation (previously known as a product licence). The MHRA now defines individual herbal medicines as either registered traditional herbal medicines or licensed herbal medicines.

In the USA dietary supplements are not classed as drugs, but the Food and Drug Administration is responsible for taking action against any unsafe dietary supplement product after it reaches the market. 

History

According to Nye and Brice (2005), “The use of mega-vitamin intervention began in the early 1950s with the treatment of schizophrenic patients.” 

Since then dietary supplements, including various formulations of multi-vitamin/mineral supplements, have been developed for a wide range of different groups including children, men, women, pregnant women and older people.

According to Adams et al (2011) dietary supplements are in widespread use as an intervention for people on the autism spectrum.

“According to a recent survey of 539 physicians, vitamin/mineral supplements are among the most widely recommended medical interventions for autism, and are recommended by 49% of physicians for children with autism”.

Current Research

We have identified three* studies of multi-vitamin/mineral supplements as an intervention for people on the autism spectrum published in English-language, peer-reviewed journals. These studies included a total of 249 individuals aged from three to sixty years old.

  • The study by Adams and Holloway (2004) was a randomised, placebo-controlled, double-blind trial which included a total of 25 individuals aged three to eight years old.The participants in the experimental group received a supplement containing 30 different ingredients for a three-month period.They reported that the supplement group showed statistically significant improvements in sleep and gastrointestinal problems compared to the placebo group.
  • The study by Adams et al (2011) was a randomised, placebo-controlled, double-blind trial which included a total of 141 individuals aged three to 60 years old.The participants in the experimental group received a supplement containing 30 different ingredients for a three-month period.They reported that the supplement group showed improvements in hyperactivity, tantrumming, receptive language, as well as overall behaviour.
  • The study by Mehl-Madrona et al (2010) was a case control study which compared multi-vitamin/mineral supplements with various medications and included 88 individuals aged two to 28 years old. Different participants in the experimental group received different versions of a multi-vitamin/mineral supplement with 36 ingredients for a minimum of three months.They reported that multi-vitamin/mineral supplements reduced self-injurious behaviours and improved overall behaviour. 

*Please note: We have not included studies with fewer than three participants on the autism spectrum or studies of individual vitamins and minerals.

Status Research

There are a number of significant limitations to all of the research studies published to date. For example

  • The study by Adams and Holloway (2004) was a small trial with only 25 participants (five of whom dropped out). The authors did not provide some key information, such as details of the dates that the trial ran, how the sample size was determined, details of the randomisation method used etc.The study did not report data on problem issues that the supplement was supposed to address (such as sleep problems and gastrointestinal problems) at the start of the study, only at the end.The tool used to collect this data was a very simple global impressions survey, based on parental observations of their children.There was no assessment of these issues by the study authors or by independent assessors.
  • The study by Mehl-Madrona et al (2010) was a retrospective case control study based on the medical records of a single medical practitioner.The parents chose which treatment their children received, the children who received medications rather than the supplement did not all receive the same medications (some received antipsychotics, some received antidepressants etc.), and the treatments received by some children changed considerably during the course of the study (for example, at the beginning of the study three children in the medication group were receiving mood stabilisers, at the end 16 children in the same group were receiving them). The children who received the supplement did not all receive the same formulation and some of them also began using omega fatty acid supplements (at the suggestion of the practitioner) or were using one or more other dietary supplements.
  • The study by Adams et al (2011) was a large trial with 141 individuals but it did not provide some key information, such as details of exactly where the trial took place, how the sample size was determined, details of the randomisation method used etc. In addition, the multi-vitamin/mineral supplement used in the trial contained levels of vitamin B6 that were well above recommended daily amounts (and could therefore have been dangerous) and also contained lithium (which is a mood stabiliser and could therefore have compromised any results).
  • The author of the study by Adams et al (2011) did not pay equal attention to all of the outcomes measures used in the way they wrote up their findings. This gave undue prominence to the one measurement tool which suggested that the supplement provided some significant benefits and failed to give sufficient prominence to the other tools which suggested that the supplement provided no benefits. The only assessment tool that found a significant difference between the supplement and the placebo was the PGI-R (Parental Global Impressions – Revised) and this tool was only used at the end of the study (whereas the others were used at the beginning and at the end). The PGI-R was the only tool mentioned in the summary and the conclusion of the study and was the only tool featured in three additional tables. The other assessment tools ATEC (Autism Treatment Evaluation Checklist), SAS (Severity of Autism Scale) and PDD-BI (Pervasive Development Disorder Behaviour Inventory) were hardly mentioned despite the fact that these tools found no significant differences between the supplement and the placebo. The authors should have made this fact much, much clearer in their reporting of the trial.  
  • The study by Adams et al (2011) was undertaken by researchers who were not independent of the intervention being studied. This is because some of the researchers are on the board of directors of a company called the Autism Nutrition Research Center which sells a product called ANRC Essentials. This is a dietary supplement based on the supplement used in the studies and which costs considerably more than most other multi-vitamin/mineral supplements. Some of the researchers involved in the study may therefore have been biased towards the intervention, however unconsciously.

For a comprehensive list of potential flaws in research studies, please see ‘Why some autism research studies are flawed’.

Ongoing Research

We are not aware of studies into multi-vitamin/mineral supplements that are currently underway.  If you know of any studies we should include please email info@researchautism.net with the details. 

Future Research

Summary of Existing Research

There is a very limited amount of low quality evidence (three group studies) on the use of multi-vitamin/mineral supplements as an intervention for people on the autism spectrum.  

This research suggests that multi-vitamin/mineral supplements may provide some benefits to some people on the autism spectrum.

However, the quality of this research is insufficient to determine if multi-vitamin/mineral supplements provide any benefits to people on the autism spectrum beyond the benefits they provide to people who are not on the autism spectrum. 

Recommendations for Future Research

There is a need for further research into the use of multi-vitamin/mineral supplements for people on the autism spectrum. Specifically there is a need for studies which

  • Use robust methodology, for example, large-scale, placebo-controlled, randomised, double-blind trials 
  • Use the same standardised outcome measures at the start and at the end of the trials and give equal prominence to all of those measures in the reporting of the trials.
  • Identify which individuals, if any, are most likely to benefit from which formulations and dosages.
  • Determine if multi-vitamin/mineral supplements can be used as one of the elements within comprehensive, multi-component, treatment models, for example, alongside special diets.
  • Compare multi-vitamin/mineral supplements with other interventions which are designed to achieve similar results, such as special diets.
  • Identify if multi-vitamin/mineral supplements have any beneficial effects in the medium to long term and in real world settings. 
  • Involve people on the autism spectrum in the design, development and evaluation of those studies. 

Studies and Trials

This section provides details of scientific studies into the effectiveness of this intervention for people with autism which have been published in English-language, peer-reviewed journals. If you know of any other studies we should include please email info@researchautism.net with the details. Thank you.

Please note that we are unable to supply publications unless we are listed as the publisher. However, if you are a UK resident you may be able to obtain them from your local public library, your college library or direct from the publisher.

Related Studies and Trials


Other Reading

This section provides details of other publications on this topic. If you know of any other publications we should include please email info@researchautism.net with the details. Thank you.

Please note that we are unable to supply publications unless we are listed as the publisher. However, if you are a UK resident you may be able to obtain them from your local public library, your college library or direct from the publisher.

Related Other Reading


Personal Accounts

We have been unable to identify any personal accounts on the use of multi-vitamin/mineral supplements in people on the autism spectrum.  If you know of any personal accounts we should include please email info@researchautism.net 

Additional Information

For reliable information on healthy eating and dietary supplements go to the NHS Choices webpages: http://www.nhs.uk/pages/home.aspx or check out British Dietetic Association Food Facts Sheets – which include fact sheets on supplements, vitamin D, calcium, probiotics, iodine, autism, diet and behaviour and learning, and more: https://www.bda.uk.com/foodfacts/home

Related Additional Information


Updated
19 Dec 2017
Last Review
01 Nov 2017
Next Review
01 Nov 2020