What Are Borderline Substances?

Borderline substances are products that sit in a grey area between food and medicine. While they are not classified as typical drugs, they are used to manage or treat medical conditions. These products include specialised foods, dietary supplements, and external applications like emollients or skin creams. They are prescribed by healthcare professionals for patients with specific medical needs.

To be classified as a borderline substance, a product must have clear evidence that it is beneficial for treating or managing certain conditions. In the UK, the approval and regulation of borderline substances are overseen by the Advisory Committee on Borderline Substances (ACBS).

These substances are particularly useful for people who cannot rely on standard treatments or diets to meet their health requirements. Examples include those with swallowing difficulties, malnutrition, coeliac disease, or chronic skin conditions like eczema.

The Role of the Advisory Committee on Borderline Substances (ACBS)

The ACBS is responsible for reviewing and recommending which products are suitable to be prescribed as borderline substances. They examine the medical evidence provided by manufacturers and assess whether a product effectively supports a given health condition. If approved, the product is listed in the Drug Tariff.

The Drug Tariff is a comprehensive guide used by pharmacists and healthcare providers in the UK. It includes details about medicines and products, including which borderline substances the NHS can fund. Without ACBS approval, a product cannot be prescribed as part of NHS treatment.

The ACBS ensures that patients have access to safe and effective products that meet certain medical needs. Their work helps to reduce confusion about which products are suitable for prescribing and ensures proper use of NHS resources.

Why Are They Called Borderline Substances?

The term “borderline” reflects the fact that these products fall between two categories: medicines and foods. They are not classed as medicines in the traditional sense, such as tablets, syrups, or injectable drugs. At the same time, they are not everyday foods or skincare products available from the supermarket.

These substances are specifically formulated to help people manage health conditions. For example, they may be designed to supplement a diet, provide nutritional support, or assist with skin recovery. Their unique purpose in medical care is what sets them apart from regular consumer products.

Let’s break this down further with categories and examples.

Types of Borderline Substances with Examples

Foods for Special Medical Purposes (FSMPs)
FSMPs are foods designed for patients with specific medical conditions that make regular diets unsuitable. These foods are often used under medical supervision. Examples:

• Gluten-free bread for people with coeliac disease.
• Lactose-free milk for individuals with lactose intolerance.
• Ketogenic formula diets for children with epilepsy.
• Nutritional drinks like Ensure or Fortisip, which provide extra calories and protein to patients who struggle with malnutrition.

Enteral Feeding Products
These are liquid formulas or semi-solid foods used through feeding tubes. Patients who cannot eat or swallow rely on these products for their nutrition. Enteral feeding is common in hospitals or for patients with complex conditions like motor neurone disease. Examples:

• Jevity and Fresubin, which provide a complete nutritional balance.
• Pepdite for children with severe allergies or digestive problems.

Dietary Supplements
Dietary supplements used as borderline substances are usually prescribed for a defined purpose, such as managing vitamin deficiencies or promoting wound healing. Examples:

• Vitamin D supplements for bone health in people with osteoporosis.
• Ferrous sulphate (an iron supplement) for those with anaemia.

External Applications for Skin Conditions
Some specialised creams and ointments are prescribed as borderline substances. These are particularly helpful for treating or managing chronic skin problems. Examples:

• Epaderm or Hydromol for eczema. These emollients moisturise and protect damaged or dry skin.
• Barrier creams for patients with incontinence, such as Cavilon cream. These reduce irritation caused by prolonged skin contact with moisture.

Metabolic Disease Products
Individuals with inherited metabolic conditions often require highly specific diets. Borderline substances play a vital part in helping them stay healthy. Examples:

• Low-protein pasta or bread for people with phenylketonuria (a condition where the body cannot process certain proteins).

Oral Nutritional Supplements (ONS)
ONS products aim to provide patients with a nutritional boost. They are often prescribed to older patients or those recovering from surgery. Examples:

• Fortisip or Calogen, which offer high-calorie, high-protein options for malnutrition.
• Glucerna, which supports individuals managing blood sugar issues, such as those with diabetes.

Thickeners for Liquids
Thickeners are prescribed for people who have swallowing difficulties, medically known as dysphagia. They reduce the risk of choking and ensure patients can consume liquids safely. Examples:

• Thick & Easy or Nutilis powder, which thickens drinks to an appropriate texture.

Who Needs Borderline Substances?

Borderline substances are prescribed for people with specific health challenges. These challenges mean they cannot fully rely on regular treatments or diets for their health needs.
Examples of people who benefit from borderline substances include:

• Patients with chronic illnesses like cancer or HIV, who may experience severe weight loss.
• Individuals recovering from surgery who require a high-calorie diet to heal.
• Those with digestive problems like Crohn’s disease, who cannot process certain types of foods.
• Babies and children with allergies or genetic conditions like phenylketonuria.
• Older adults with malnutrition in care settings.
• Patients with neurological issues that reduce their ability to swallow, such as following a stroke.

For these individuals, borderline substances can improve quality of life and reduce complications related to their medical condition.

Can Borderline Substances Be Bought Over the Counter?

Some borderline substances are available to buy in pharmacies or specialist shops. For example, gluten-free bread can be purchased by anyone, even without a prescription. However, many products are often much more expensive at retail prices. Patients who need these items regularly are typically encouraged to get them through a prescription, especially for long-term conditions.

For products listed in the Drug Tariff, GPs can prescribe these items under the NHS. This ensures patients with specific health conditions can access products without facing additional financial burden.

How Are They Different from Medicines?

Medicines, such as antibiotics or painkillers, are designed to treat or cure specific conditions. They usually have an active ingredient that directly affects the body’s processes.

Borderline substances, on the other hand, do not cure illnesses. Instead, they support the body’s needs by addressing gaps caused by illness or disability. For example:

• A high-calorie nutritional drink helps someone gain weight after surgery.
• A gluten-free loaf prevents symptoms in a coeliac patient.
• A cream for dry skin offers relief for patients with eczema.

While medicines target specific biological processes, borderline substances help improve overall health and wellbeing in a safe and controlled manner.

Limitations of Borderline Substances

Although borderline substances are useful, they have limitations. For example:

• They are not a replacement for regular medical treatments where medicines are required.
• Some products might require long-term use and frequent monitoring to ensure they are still effective.
• If prescribed incorrectly, they might not offer much benefit to the patient.

It is important for GPs, nurses, and dietitians to assess whether a patient truly needs a borderline substance. Each person’s health needs must be reviewed carefully to avoid unnecessary treatments.

Final Thoughts

Borderline substances play a special role in healthcare. They provide patients with a tailored approach to managing conditions through nutrition, skin care, or supplementary products. These items help people who face unique challenges due to illness, disability, or long-term health conditions.

Examples such as nutritional drinks, gluten-free foods, skin creams, and enteral feeding solutions show how wide this category is. Each product is designed with a clear purpose: to improve health when regular diets or treatments fall short.

The regulation by the ACBS ensures these products are evidence-based, safe, and cost-effective for the NHS. With growing recognition of the need for personalised healthcare, borderline substances are an essential part of ensuring everyone receives the care they need.