There’s a dreamy picture on the cover, but instead of cheery recipes and holiday snaps, this summer I have been diving into additional research for you.

I want to highlight where some simple changes could make a massive difference to your wellbeing, now and in the future. That’s my idea of fun.

So, this summer, you have a newsletter focusing, not on sun tan oil, but on vegetable oil.

Oh yeah – exciting stuff.

But before you click away, please spend two minutes reading through this newsletter, because it might be Just One Thing (bless you, Michael Mosley) that shifts your course from one destination to a much better one, so please, read on.

It has been coming to light for a while that vegetable oils are not the healthy option we’ve all been led to believe.

I did not take this seriously when I first heard about it – I mean, vegetable oil looks so pure and innocuous. Surely it must be better for us than those tasteless blocks of solid fat we used to make pastry with, when I was a child?

We have been fed the story for the last 50 years or so that meat fats, particularly saturated fats are bad for our hearts, and vegetable oils are much better[1].

Most health-conscious people dutifully gave up their butter and switched to margarine when they heard this story, stopped using lard for cooking, replaced it with pale, liquid “vegetable” oils – seed oils would be a more accurate description – soya, sunflower, rapeseed (canola), corn oil – and cut the fat off their meat.

My own father, who developed angina in his forties after smoking, went on to a career making margarine. He was thinking that he was doing the world a favour and helping to prevent heart disease.

Poor deluded man. It turns out that the opposite is true[2],[3].

Biochemists and nutrition scientists were trying to flag up the issues with the hydrogenation that made vegetable oils solid, but produced trans-fats for decades[4], but the industry lobby was very powerful, and trans fats in the food supply only became banned in some countries since 2004.

Here in the UK there is still only a voluntary agreement – no outright ban.

Now we use palm oil from Indonesia as a replacement, and have massive deforestation –the law of unintended consequences…

Trans fats are still with us. They are made when we heat vegetable oils, especially polyunsaturated and monounsaturated oils, in frying pans, in restaurants and particularly in deep fat friers [5].

On top of that, heated vegetable oils produce about 150 different other artificial compounds that are deeply toxic and cancer-causing [6]. The acrid smell of burnt vegetable oils is acrylamide – a sort of vaporised, brown, toxic varnish that is almost impossible to scrub off surfaces [7].

People who cook over frying pans, woks and deep fat friers in poorly ventilated kitchens in the catering trade – have been found to have higher levels of lung cancer, even though they don’t smoke [8], [9].

Other compounds that are created in heated vegetable oils, damage the gut lining when eaten. These include formaldehyde – so toxic that it is used to preserve dead bodies.

When rats were fed heated vegetable oils as 10% of their calories, they developed gastric ulcers. Their levels of oxidised cholesterol rose dramatically, leading to 100 fold increase in inflammatory markers, atherosclerosis and heart damage. Unsurprisingly, they died early [10].

Mice, whom you might imagine are designed to eat more seeds than we are, start getting increased rates of cancer if they ate between 4-10% of their calories as linoleic acid [11]. This has also been found in research on humans [12], [13].

It is worth bearing in mind that many people are eating up to 25% of their calories in the form of heated vegetable oils from ultra-processed foods. [14] And people wonder why the rates of all chronic disease are increasing – this is a major factor.

We can burn saturated fats for energy, store them, or use them to build more cells. Vegetable oils, when burned for energy, react with oxygen and release a lot of damaging free-radicals, like dangerous sparks from a fire. Our body does not want to burn these dangerous fats, so it tends to store them away instead.

Obesity rates have risen steadily in line with the proportion of vegetable oil use, even though people now are eating fewer calories, saturated fat and sugar than they were. Overweight people are storing about 25% of their fat as linoleic acid [15].

To make it worse, a compound called 4HNE from linoleic acid accumulates in fat cells, making them grow bigger until they cannot store any more without leaking [16]. These fat cells then cannot listen to insulin’s signals to take in any spare blood glucose and turn it into fat. They become insulin-resistant, as a protective mechanism for themselves, but this keeps blood sugar in the bloodstream, and therefore promotes diabetes. These cells are in distress, so they send out pro-inflammatory signals to get help from the immune system. Being so full, they leak these reactive fats into the bloodstream, raising triglycerides, getting oxidised and promoting inflammation throughout the body.

When fats are carried around your body in your oxygen-rich bloodstream for storage, they are carried in the fat-taxis known as LDL. Blood vessel walls need daily maintenance, due to the forces of blood pressure going round, and cholesterol is essential to repair them. The problem is, much of the available cholesterol is now oxidised and damaged, which triggers the white blood cells to go after it. They dive into the blood vessel wall, weakening it, and they swallow the oxidised cholesterol whole. (This process is just like white cells going after bacteria and forming a thin-walled spot.)

These white blood cells then die, creating a fatty plaque of oxidised cholesterol inside the blood vessel. The bloodstream tries to strengthen the weakened area by building more cells on top, maybe adding some calcium for good measure. This whole process creates inflammation, narrowing and clotting in the blood vessel walls. It is designed to be protective, and prevent you springing any leaks, but the end result is heart and cardiovascular disease in action [17].

To add to the catalogue of woes, linoleic acid disrupts the function in the walls of your cell batteries, your mitochondria. This is where you make your energy.

When exposed to oxygen, a by-product of ordinary energy production, these oils “rust”[18]- they get bent out of shape, and stop working as they should. Your energy levels go right down because your batteries are damaged. This is also connected to the surge in long-lasting fatigue disorders not relieved by rest, and the general “tired all the time “feeling associated with every chronic disease [19].

Image credit: Mitochondrial Medicine Society and MITOAction.org

What’s even worse, these damaged cells and mitochondria don’t die – linoleic acid interferes with sending out the “I’m damaged – take me out” signal, so the cells hang on, reproducing their damage, and not working properly for the organ they live in. This can lead to ongoing fatigue, and poor function. It can also lead to tumours [20].

To top it off, and this still isn’t everything – earlier research found that people on a high polyunsaturated fat diet with lots of Omega 6, were more prone to depression and mood disorders [21], and there was an increase in suicide and violence.

When you realise that around 60% of the average teenagers diet consists of ultra-processed foods containing high linoleic, heated vegetable oil, that puts another perspective on the links between poor nutrition and delinquent behaviour. [22]

All of this is deeply depressing – perhaps hardly the subject for a Summer Newsletter.

However, now you know this information, you can make different choices that benefit your health, and that of your family, increase your energy and reduce your risk of nearly all chronic diseases.

That has to be worth a little mental discomfort, at least in my view. As my job is to look after your health and wellbeing, I felt I had to share this knowledge with you.

This newsletter doesn’t make easy reading for vegetarians in particular, so I apologise if this information is discomforting.

We humans evolved while eating meat, fish, shellfish, leafy vegetables, root vegetables and nuts. These contained the most beneficial sources of fat, in the right sort of proportions, with very little linoleic acid, which is found in seed oils. Seeds were rarely worth chewing.

For the vegetarians among you, coconut oil is fine and safe for cooking, frying and roasting. Ghee is great and very stable for cooking, and butter is delicious but tends to

burn, so better in moist cooking such as baking or steaming rather than for frying.

Someone is bound to ask about olive oil and avocado oil. They do contain some heart-healthy antioxidants and vitamin E, but still contain quite a lot of linoleic acid, so use them in moderation over your salads, but don’t cook with them.

In summary, I’m recommending that those of you who are not committed vegetarians, go back to eating much more of those Palaeolithic-type foods, and ditch the processed vegetable oils in favour of good old-fashioned dripping! Duck fat, lard and dripping are great for roasting.

Seriously, let them eat lard!

If you want to know more about straightforward ways to get round the complexities of heart disease, I’m running a new programme in September, called “3 Months to a Healthier Heart”.

You can find more details by clicking the link below, and there is also an option to just book a 20 minute complementary chat with me.

It might be exactly what you need.

References:

[1] Keys, “Diet and the Epidemiology of Coronary Heart Disease”: Ancel Keys, Joseph Anderson, and Francisco Grande, “Fats and Disease,” Lancet 272, no. 6796 (1957): 992–993.[2] https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11123895/Newport MT, Dayrit FM. The Lipid-Heart Hypothesis and the Keys Equation Defined the Dietary Guidelines but Ignored the Impact of Trans-Fat and High Linoleic Acid Consumption. Nutrients. 2024 May 11;16(10):1447. doi: 10.3390/nu16101447. PMID:38794685; PMCID: PMC11123895.[3] Stender S, Dyerberg J. Influence of trans fatty acids on health. Ann Nutri Metab.2004;48(2):61-6. doi: 10.1159/000075591. Pub 2003 Dec 16. PMID: 14679314.

https://pubmed.ncbi.nlm.nih.gov/14679314/. See also https://www.diabetes.co.uk/food/trans-fats.html

[4] Patricia V. Johnston, Ogden C. Johnson, and Fred A. Kummerow, Occurrence of Trans Fatty Acids in Human Tissue,” Science 126, no. 3276 (1957):698–699.

[5] A. Saari Callan et al., “4-Hydroxynonenal (HNE), a Toxic Aldehyde in French Fries from Fast Food Restaurants,” poster presentation at the HNE Symposium of the 16th Bi-Annual Conference of the Free Radical Society and HNE Symposium, London, September 1–9, 2012.

[6 Randall Wood, Fred Chumbler, and Rex Wiegand, “Incorporation of Dietary cis and trans Isomers of Octadecenoate in Lipid Classes of Liver and Hepatoma, ”Journal of Biological Chemistry 252, no. 6 (1977): 1965–1970.

[7] “Studies to Determine the Nature of the Damage to the Nutritive Value of Some Vegetable Oils from Heat Treatment: IV. Ethyl Esters of Heat Polymerized Linseed, Soybean and Sunflower Seed Oils,” Journal of Nutrition 60, no. 1 (1956): 13–24. See also John S. Andrews et al., “Toxicity of Air-Oxidized Soybean Oil,” Journal of Nutrition 70, no.2 (1960): 199–210; and Samuel M. Greenberg and A. C. Frazer

[8] “A Survey of Cancer and Occupation of Young and Middle Aged Men. Cancers of the Respiratory Tract,” British Journal of Industrial Medicine 43, no. 5 (1986): 332–338; E. Lund and J. K. Borgan, “Cancer Mortality among Cooks,” Tesseract for Den Norske Legeforening 107 (1987): 2635–2637; I. Coppa and C. Minder, “Oral, Pharyngeal and Laryngeal Cancer as a Cause of Death among Swiss Cooks,” Scandinavian Journal of Work, Environment and Health 18 (1992): 287–292. See, also, She-Ching Wu and Gow-Chin Yen, “Effects of Cooking Oil Fumes on the Genotoxicity and Oxidative Stress in Human Lung Carcinoma (A-549) Cells,” Toxicology in Vitro 18, no. 5 (2004): 571–580.

[9] Fidler-Bensouda, M. M., Torre, L. A., Bray, F., Ferly, J., & Jemal, A. (2020). Lung Cancer Incidence in Young Women Vs. Young Men: A Systematic Analysis in 40Countries. International Journal of Cancer, 147(3), 811–819.https://doi.org/10.1002/ijc.32809

[10] “Some Factors Affecting the Growth and Development of Rats Fed Rancid Fat, ”Journal of Nutrition 50, no. 4 (1953): 421–440.Randall Wood, Fred Chumbler, and Rewidened, “Incorporation of Dietary cis and trans Isomers of Octadecenoate in Lipid Classes of Liver and Hepatoma, “Journal of Biological Chemistry 252, no. 6 (1977): 1965–1970.

[11] Rose DP, Hatala MA, Connolly JM, Rayburn J. Effect of diets containing different levels of linoleic acid on human breast cancer growth and lung metastasis in nude mice. Cancer Res. 1993 Oct 1;53(19):4686-90. PMID: 8402646.https://pubmed.ncbi.nlm.nih.gov/8402646/

[12] “A Survey of Cancer and Occupation of Young and Middle Aged Men. Cancers of the Respiratory Tract,” British Journal of Industrial Medicine 43, no. 5 (1986): 332–338; E. Lund and J. K. Borgan, “Cancer Mortality among Cooks,” Tesseract for Den Norske Legeforening 107 (1987): 2635–2637; I. Coppa and C. Minder, “Oral, Pharyngeal and Laryngeal Cancer as a Cause of Death among Swiss Cooks,” Scandinavian Journal of

Work, Environment and Health 18 (1992): 287–292. See, also, She-Ching Wu and Gow-Chin Yen, “Effects of Cooking Oil Fumes on the Genotoxicity and Oxidative Stress in Human Lung Carcinoma (A-549) Cells,” Toxicology in Vitro 18, no. 5 (2004): 571–580.

[13] Fidler-Bensouda, M. M., Torre, L. A., Bray, F., Ferly, J., & Jemal, A. (2020). Lung Cancer Incidence in Young Women Vs. Young Men: A Systematic Analysis in 40Countries. International Journal of Cancer, 147(3), 811–819.https://doi.org/10.1002/ijc.32809.

[14] Morton Lee Pearce and Seymour Dayton, “Incidence of Cancer in Men on a Diet High in Polyunsaturated Fat,” Lancet 297, no. 7697 (1971): 464–467.

[15] Naughton SS, Mathai ML, Erycid DH, McAinch AJ. Linoleic acid and the pathogenesis of obesity. Prostaglandins Other Lipid Mediate. 2016 Sep;125:90-9. doi:10.1016/j.prostaglandins.2016.06.003. Pub 2016 Jun 24. PMID: 27350414.

[16] Ester Bauer H, Schaur RJ, Zollner H. Chemistry and biochemistry of 4-hydroxynonenal, malonaldehyde and related aldehydes. Free Radic Boil Med.1991;11(1):81-128. doi: 10.1016/0891-5849(91)90192-6. PMID: 1937131.https://pubmed.ncbi.nlm.nih.gov/1937131/

[17] Asselin C, Ducharme A, Ntimama T, Ruiz M, Fortier A, Guertin MC, Lavoie J, Diaz A, Levy E, Tardif JC, Des Rosier C. Circulating levels of linoleic acid and HDL-cholesterol are major determinants of 4-hydroxynonenal protein adducts in patients with heart failure. Redox Biol. 2013 Dec 18;2:148-55. doi: 10.1016/j.redox.2013.12.009. PMID: 24494189;PMCID: PMC3909262.

[18] Falabella M, Vernon HJ, Hanna MG, Claypool SM, Patently RDS. Cardiolipin, Mitochondria, and Neurological Disease. Trends Endocrinol Meta. 2021 Apr;32(4):224-237. doi: 10.1016/j.tem.2021.01.006. Pub 2021 Feb 24. PMID: 33640250; PMCID:PMC8277580.

[19] Yapa NMB, Lesniak V, Reljic B, Ryan MT. Mitochondrial dynamics in health and disease. FEBS Lett. 2021 Apr;595(8):1184-1204. doi: 10.1002/1873-3468.14077. Epub2021 Apr 5. PMID: 33742459.

[20] Randall Wood, Fred Chumbler, and Rex Wiegand, “Incorporation of Dietary cis and trans Isomers of Octadecenoate in Lipid Classes of Liver and Hepatoma, “Journal of Biological Chemistry 252, no. 6 (1977): 1965–1970

[21] Joseph R. Hibbeln and Norman Salem Jr., “Dietary Polyunsaturated Fatty Acids and Depression: When Cholesterol Does Not Satisfy,” American Journal of Clinical Nutrition62, no. 1 (1995): 1–9

[22] J. R. Hibbeln et al.,“Do Plasma Polyunsaturates Predict Hostility and Violence?” in Nutrition and Fitness: Metabolic and Behaviour Aspects in Health and Disease, World Review of Nutrition and Dietetics 82, eds., A. P. Simopoulos and K. N. Pavlou (Basel, Switzerland: Karger, 1996):175–186.