Weight Loss with Tuberous Sclerosis Complex in South Africa

Tuberous Sclerosis Complex (TSC) is an autosomal dominant genetic disorder caused by loss-of-function mutations in either the TSC1 gene (encoding hamartin, chromosome 9q34) or TSC2 gene (encoding tuberin, chromosome 16p13.3). Hamartin and tuberin form a complex that normally inhibits the mTOR (mechanistic target of rapamycin) signalling pathway — a master regulator of cell growth and proliferation. When either gene is mutated, mTOR runs unchecked, causing benign tumour-like growths (hamartomas) to form in virtually every organ: brain (cortical tubers, subependymal nodules, SEGAs), kidneys (angiomyolipomas), lungs (lymphangioleiomyomatosis in women), skin (facial angiofibromas, shagreen patches), and heart (rhabdomyomas in infants).

TSC affects approximately 1 in 6 000 individuals worldwide. In South Africa, diagnosis is confirmed by genetic testing available through the NHLS molecular genetics service, clinical criteria (the TSC Diagnostic Criteria consensus 2012), and neuroimaging. The TSC Association South Africa provides family support and specialist referral assistance.

Why Weight Gain Is Common in TSC

Anti-Epileptic Drug (AED) Weight Effects

Epilepsy affects up to 90% of TSC patients, often presenting in the first year of life as infantile spasms and evolving into multiple seizure types. The medications used carry significant weight implications:

mTOR Inhibitors: Everolimus and Sirolimus

Everolimus (Afinitor) and sirolimus (Rapamune) directly target the mTOR pathway — the same pathway that is overactive in TSC. They are approved for subependymal giant cell astrocytomas (SEGAs), renal angiomyolipomas, and pulmonary LAM in TSC. Their metabolic effects are complex:

• Hyperglycaemia — mTOR inhibition impairs insulin signalling; new-onset diabetes or worsening glucose control occurs in up to 15-20% of patients
• Hyperlipidaemia — elevated triglycerides and LDL cholesterol in many patients
• Appetite changes — mouth sores (stomatitis) reduce oral intake and may paradoxically cause weight loss or nutritional deficiency
• Fat redistribution — some patients develop increased truncal adiposity despite stable or reduced total weight

If you are on everolimus or sirolimus, your metabolic specialist should monitor fasting glucose, HbA1c, and fasting lipids at each 3-6 month review. Diet must specifically target preventing hyperglycaemia (low GI eating) and hyperlipidaemia (Mediterranean pattern).

Reduced Activity from Neurological and Renal Involvement

Intellectual disability (present in approximately 50% of TSC patients), autism spectrum disorder (up to 50%), and severe epilepsy all reduce physical activity independently of cardiovascular fitness. Renal angiomyolipomas — particularly those over 3-4 cm — carry a risk of spontaneous haemorrhage with vigorous contact exercise, further restricting activity options.

The Ketogenic Diet in TSC: A Dual-Benefit Strategy

The ketogenic diet occupies a unique and evidence-based position in TSC management because it addresses both epilepsy and weight simultaneously — though in opposite directions to what might be expected.

Ketogenic Diet for Seizure Control

Multiple studies, including a 2018 randomised controlled trial specifically in TSC, have demonstrated significant seizure reduction (>50% in approximately 30-40% of patients) on the classical ketogenic diet or modified Atkins diet. The mechanism may involve reduced mTOR activation by ketosis, altered neural excitability, and improved mitochondrial function.

Weight Implications of Ketogenic Therapy

The classical ketogenic diet (4:1 or 3:1 fat-to-protein+carb ratio) is very high in fat and can be calorically dense — in growing children, the goal is seizure control while maintaining growth, not weight loss. In overweight TSC adults, a modified approach (modified Atkins or low-glycaemic index treatment — LGIT) can provide seizure benefits while also supporting modest weight reduction. Key differences:

In South Africa, dietitians trained in ketogenic diets for epilepsy are based primarily at the academic neurology centres: Red Cross War Memorial Children's Hospital (Cape Town), Charlotte Maxeke Johannesburg Academic Hospital, and Inkosi Albert Luthuli Central Hospital (Durban). A referral from a neurologist is required.

Nutrition Without Ketogenic Therapy

If ketogenic therapy is not appropriate or desired, a Mediterranean-pattern diet achieves multiple goals simultaneously:

Core Principles

• Low GI carbohydrates — essential to counteract everolimus-induced hyperglycaemia; oats, legumes, sweet potato, whole grain bread
• Heart-healthy fats — olive oil, avocado, nuts, oily fish; addresses everolimus-related hyperlipidaemia
• High-quality protein — eggs, chicken, fish, legumes; 1.2-1.6 g/kg/day; maintains muscle during periods of reduced activity
• Anti-inflammatory foods — oily fish, berries, dark leafy greens, turmeric; reduces systemic inflammation that may amplify seizure susceptibility
• Limit refined sugar — particularly important with mTOR inhibitor-induced glucose dysregulation
• Rooibos tea — emerging evidence for mTOR pathway modulation by aspalathin; safe; anti-inflammatory; 3-4 cups daily

Managing Stomatitis on mTOR Inhibitors

Mouth sores from everolimus/sirolimus can severely impair eating. Strategies:

• Soft, cool or room-temperature foods — yoghurt, maas, smoothies, scrambled eggs, mashed sweet potato
• Avoid acidic foods (citrus, tomatoes, vinegar) during stomatitis flares
• Avoid very spicy food, alcohol, and rough-textured food
• Nutrient-dense liquids (protein smoothies, meal replacement drinks like Ensure or local equivalents) maintain intake when solids are painful
• Steroid mouth rinses (dexamethasone solution) prescribed by oncologist or neurologist reduce severity

Exercise in TSC

Exercise That Works in TSC

• Walking — safe for most TSC patients; great starting point; aim for 20-30 min 5x/week
• Swimming — low-impact; safe regardless of angiomyolipoma status (no direct kidney impact); seizure safety requires never swimming alone
• Stationary cycling — controlled intensity; no fall risk; suitable for patients with balance or neurological impairment
• Yoga and stretching — gentle yoga reduces cortisol (stress-triggered seizure exacerbation); improves flexibility and body awareness
• Dance and rhythm activities — accessible for TSC patients with autism who respond well to music; social benefit

Seizure Safety During Exercise

• Never exercise alone — a buddy system or supervised environment is essential
• Wear a medic alert bracelet identifying TSC and seizure disorder
• Carry a rescue medication (midazolam buccal — Buccolam, available on specialist prescription in SA) for prolonged seizures
• Avoid exercise when seizure frequency has recently increased — check with neurologist
• Avoid overheating — hyperthermia can lower seizure threshold; exercise in cool environments; hydrate well

Practical Day Plan for TSC Adults

• Breakfast: Rolled oats with berries and a handful of walnuts; rooibos tea
• Morning: 20-30 min walk or stationary cycling; with carer or family member
• Lunch: Grilled mackerel or sardines on whole grain bread; side salad with olive oil dressing
• Afternoon: Snack: handful almonds + an apple
• Dinner: Chicken or legume stew with sweet potato and green vegetables; low sodium home cooking
• Evening: Light stretching or gentle yoga; rooibos before bed