Powering Up Your Immunity – my step by step guide

man sneezing

At this time of year I have a simple three step strategy to turn on my immune system ready for winter.

Step 1: Go Keto for five days

By going ketogenic for 5 to 7 days you can reboot your immune system. Astonishingly, in animal studies, doing this a few times can reverse auto-immune diseases by resetting the immune system. Think of this as your cells, including immune cells, having two engines – one that runs on carbs the other on fat. If you switch off your carb engine for five days, running on ketones instead, this engine gets a clean up, and immune cells get tuned up, much like putting your car in for a service.

How to do this is explained in my Hybrid Diet book but, put simply, start by having a low GL dinner at 6 or 7pm, then my Hybrid Latté in the morning, using Ketofast (C8 oil) and lunch at 1pm – perhaps salmon and salad or coconut sautéed spinach or an asparagus omelette, and an afternoon snack of taramasalata and crudités, followed by a Hybrid high fat dinner from the book. That’ll get you started and into ketosis. I’m also doing a winter Hybrid Retreat from January 17th to 24th.

Step 2 – build vitamin D stores

In the Autumn the body lays down stores of vitamin D for the months to come so get outside as much as you can, exposing your arms and face to the sun. Also, supplement 15mcg (600iu) every day in your multivitamin – that’s what’s in mine which is three times more than most, and I’m going to take that throughout the winter. You can boost vitamin D stores easily with 25mcg (1000iu) drops, taking 3 drops a week throughout the winter. It stores so you don’t have to take it every day. (If you go somewhere hot on holiday there’s no need to do this during your holiday, nor for a couple of weeks after). If you’ve had your vitamin D level measured you want to get it above 75nmol/l for maximum immune protection.

Step 3 – stock up on vitamin C, zinc and black elderberry

The three most potent remedies for killing a cold are vitamin C, taking 1 gram an hour from first symptoms, high dose zinc and black elderberry.

Viruses get into body cells by puncturing their walls with tiny spikes made of a substance called hemagglutinin. Black elderberry disarms these spikes by binding to them and preventing them from penetrating the cell membrane.

In a double blind controlled trial elderberry extract, given to people with various strains of flu, showed a significant improvement in symptoms – fever, cough, muscle pain – in 20 per cent of patients within 24 hours, and in a further 73 per cent of patients within 48 hours. After three days 90 per cent had complete relief of their symptoms compared to another group on a placebo, who look at least six days to recover. A more recent study found that giving elderberry extract 4 times a day, versus placebo, cut duration of flu symptoms by 4 days.1

Zinc supports healthy immune function and enhances immune T-cell activity, which is what fights infections. In a review of seven trials2 ‘The mean common cold duration was 33% shorter for the zinc groups’ but this only applies to studies taking over 25 to 50mg a day, for short term use during a cold. My multi gives 15mg so I want another 10-35mg during a day with cold symptoms.

I recommend half this level (50mg) in zinc lozenges, for short-term use only or supplementing 25mg a day.

Vitamin C works but you have to have a high dose. Even in studies giving 2 grams a day, which is what I take every day, you get shorter colds and less symptom severity. But in two controlled trials found a statistically significant dose–response, for the duration of common cold symptoms, with up to 6–8 g/day of vitamin C. I recommend 1 gram an hour or 2 grams every two hours, at the first onset of a cold.

By taking a vitamin C supplement that also contains zinc and black elderberry you’ll get significant amounts of all three natural remedies if you take an hourly dose until symptoms are gone.

My vitamin C formula – either tablets or powder, gives 3mg of zinc and 50mg of black elderberry extract per 1 gram of vitamin C. So, if you take 10 in a day you’re getting 30mg of zinc and 500mg of black elderberry, which is optimal short-term.

Immune-friendly foods include carrots, beetroot, sweet potatoes, berries (can buy these frozen when they are not in season), garlic and shiitake mushrooms. Eat what you can raw, and lightly steam the rest. Avoid frying anything as this introduces harmful free radicals that increase your toxic load. Herbs and spices contain immune-supporting nutrients – for example, add turmeric to rice; grate ginger into stir fries or on to vegetables or make tea from it. My vitamin C also includes ginger. I juice ginger and make ice cubes so you can pop one in boiling water, add a shot of Blueberry or CherryActive when you fancy a hot drink or if you have a sore throat. Avoid sugar – it can suppress the immune system.

Further information can be found in my book Boost Your Immune System.

ImmuneC, High Strengh ImmuneC powder and Ketofast are available from HOLFORDirect.


1. Z. Zakay-Rones et al.,‘Inhibition of several strains of influenza virus in vitro and reduction of symptoms by an elderberry extract (Sambucus nigra L.) during an outbreak of influenza B Panama’, Journal of Alternative and Complementary Medicine (1995), vol. 1(4). ; Z. Zakay-Rones et al., ‘Randomized study of the efficacy and safety of oral elderberry extract in the treatment of influenza A and B virus infections’, Journal of International Medical Research (2004), vol. 32(2), pp. 132-140.

2. H Hemila,‘Zinc lozenges and the common cold: a meta-analysis comparing zinc acetate and zinc gluconate’, and the role of zinc dosage JRSM Open 2017 May 2;8(5):2054270417694291. 2017